D&D 5E Boss Fight Help

So my adventurers have reached the final boss of the dungeon. Some background on the story first...

The Adventurers were chilling out in this town for various reasons when it was suddenly attacked by an army of undead and shapeshifters. Although the seige was repelled, it is revealed that the shapeshifters had used the battle as a distraction to kidnap several prominent citizens. Thus, the Adventurers were given the task of saving the VIPs. A princess (a high level wizard) and a few elite soldiers ventured underground with the Adventurers.

The Adventurers discover a hive of the shapeshifters situated beneath the capital of the kingdom. However, the corridors constantly shift and change. This leads the Adventurers to become separated from the NPCs for most of the dungeon where they encounter undead, shapeshifters, random monsters, and slaadi for some reason. Eventually the Adventurers find the bottom layer of the hive where the princess was held captive and her guards killed in some dark necromantic ritual. In the next room they find the queen of the hive.

After a short conversation with the queen, the Adventurers attack. Several drones drop from the ceiling, taking on the appearance of the Adventurers, and sow confusion. Now, at present time, the Cleric decides to cast Spirit Guardians...

Now for the big question, according to the spell description "you can designate any number of creatures you can see to be unaffected by it". How do y'all rule as "designate"? Does the cleric pick those unaffected by name or by sight? Would "my party" or "my allies" qualify as an appropriate designation, or do they have to pick individual creatures?

This spell is capable of wiping out every single drone in one round. Last time the cleric used it, it killed 30+ CR 3 creatures in a single round. Keep in mind that the cleric is level 6 at this time.

Here are the stats for the enemies in the boss fight...

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Changeling Drone
AC: 15 (natural armor)
HP: 16
Speed: 40 ft., flying 60 ft., climb 30 ft.

STR 12 (+1)
DEX 15 (+2)
CON 13 (+1)
INT 8 (-1)
WIS 12 (+1)
CHA 14 (+2)
Skills: Perception +3, Stealth +4, Survival +3, Deception +6
Senses: darkvision 60 ft., passive Perception 13
Languages: Changeling, Common
Challenge 3 (700 XP)

Shapechanger: The changeling can use its action to polymorph into a Small or Medium humanoid it has seen, or back into its true form. Its statistics, other than its size, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Chameleon Carapace: The changeling can change the color of its carapace to match the color and texture of its surroundings. As a result, it has advantage on Dexterity (Stealth) checks made to hide.

Standing Leap: The changeling's long jump is up to 30 feet and its high jump is up to 15 feet, with or without a running start.

Hive Mind: Groups of three or more changelings gain advantage on Perception checks, Dex and Wis saves, attack rolls, and gain +1 to AC.

ACTIONS
Multiattack: The changeling makes two attacks: one with its bite and one with its claws.

Bite: Melee Weapon Attack: +3 to hit, reach 5 ft., one creature. Hit: 4 (1d6 + 1) piercing damage, and the target must succeed on a DC 11 Constitution saving throw or be poisoned for 1 minute. If the saving throw fails by 5 or more, the target is also paralyzed while poisoned in this way. The poisoned target can
repeat the saving throw on each of its turns , ending the effect on itself on a success.

Claws: Melee Weapon Attack: +3 to hit, reach 5 ft. , one target. Hit: 6 (2d4 + 1) slashing damage.

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Changeling Praetorian Elite
Large monstrosity, chaotic evil

Armor Class 19 (natural armor)
Hit Points: 110
Speed 30ft., burrow 20 ft.
STR 22 (+6)
DEX 13 (+1)
CON 16 (+3)
INT 9 (-1)
WIS 10 (+0)
CHA 10 (+0)

Senses darkvision 120ft., tremorsense 60ft.,
passive Perception 10
Languages: Changeling
Challenge 5 (1 ,800 XP)

Confusing Gaze: When a creature starts its turn within 30 feet of the Changeling Praetorian and is able to see the Praetorian's eyes, the
Praetorian can magically force it to make a DC 15 Charisma saving throw, unless the umber hulk is incapacitated. On a failed saving throw, the creature can't take reactions until the start of its next turn and rolls a d8 to determine what it does during that turn. On a 1 to 4, the creature does nothing. On a 5 or 6, the creature takes no action but uses all its movement to move in a random direction. On a 1 or 8, the creature makes one melee attack against a random creature, or it does nothing if no creature is within reach. Unless surprised, a creature can avert its eyes to avoid the saving throw at the start of its turn. If the creature does so, it can't see the umber hulk until the start of its next turn, when it can avert its eyes again. If the creature looks at the Praetorian in the meantime, it must immediately make the save.

Tunneler: The Changeling Praetorian can burrow through solid rock at half its burrowing speed and leaves a 5 foot-wide, 8-foot-high tunnel in its wake.

ACTIONS
Multiattack: The Changeling Praetorian makes three attacks: two with its claws and one with its mandibles.
Claw: Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 6) slashing damage.
Mandibles: Melee Weapon Attack: +9 to hit, reach 5 ft. , one target. Hit: 14 (2d8 + 6) slashing damage.

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Changeling Queen
Huge Monstrosity
Chaotic Evil

AC: 17 (natural armor)
HP: 206
Speed: 30ft, flying 60 ft.

STR: 14 (+2)
DEX: 17 (+3)
CON: 14 (+2)
INT: 15 (+2)
WIS: 15 (+2)
CHA: 20 (+5)

Condition Immunities: Charmed
Damage Resistances: Psychic, Poison
Skills: Stealth +7, Arcana +6, History +6, Insight +6, Perception +6, Deception +9, Persuasion +9
Senses: Blindsight 10ft, Darkvision 60 ft, Passive Perception 17,
Languages: Changeling, Common, Elvish, Gnomish, Dwarvish
Challenge: 10

Shapechanger: The changeling can use its action to polymorph into a Small or Medium humanoid it has seen, or back into its true form. Its statistics, other than its size, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Chameleon Carapace: The changeling can change the color of its carapace to match the color and texture of its surroundings. As a result, it has advantage on Dexterity (Stealth) checks made to hide.

Standing Leap: The changeling's long jump is up to 30 feet and its high jump is up to 15 feet, with or without a running start.

Confusing Gaze: When a creature starts its turn within 30 feet of the Changeling Queen and is able to see the her eyes, she can magically force it to make a DC 18 Charisma saving throw, unless she is incapacitated. On a failed saving throw, the creature can't take reactions until the start of its next turn and rolls a d8 to determine what it does during that turn. On a 1 to 4, the creature does nothing. On a 5 or 6, the creature takes no action but uses all its movement to move in a random direction. On a 1 or 8, the creature makes one melee attack against a random creature, or it does nothing if no creature is within reach. Unless surprised, a creature can avert its eyes to avoid the saving throw at the start of its turn. If the creature does so, it can't see the umber hulk until the start of its next turn, when it can avert its eyes again. If the creature looks at the Praetorian in the meantime, it must immediately make the save.

Innate Spellcasting: Level 13 spellcaster. CHA. +10 spell bonus. Save DC 18.
At will: Minor Illusion, Light, Eldritch Blast, Friends, Poison Spray
3/day: Sleep, Detect Thoughts, Vampiric Touch
1/day: Mass Suggestion, Disintegrate

ACTIONS
Multiattack: The Changeling Queen makes two attacks: one with its bite and one with its claws.

Bite: Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 4 (2d6 + 3) piercing damage, and the target must succeed on a DC 14 Constitution saving throw or be poisoned for 1 minute. If the saving throw fails by 5 or more, the target is also paralyzed while poisoned in this way. The poisoned target can
repeat the saving throw on each of its turns , ending the effect on itself on a success.

Claws: Melee Weapon Attack: +7 to hit, reach 5 ft. , one target. Hit: 6 (4d4 + 3) slashing damage.

Charm: One humanoid that the Changeling Queen can see within 30 feet of it must succeed on a DC 18 Wisdom saving throw or be magically charmed for 1 day. The charmed target obeys Chrysalis's verbal or telepathic commands. If the target suffers any harm or receives a suicidal command, it can repeat the saving throw, ending the effect on a success. If the target successfully saves against the effect, or if the effect on it ends, the target is immune to the Queen's Charm for the next 24 hours. She can have only one target charmed at a time. If it charms another, the effect on the previous target ends.

TheNoremac42 said:

Now for the big question, according to the spell description "you can designate any number of creatures you can see to be unaffected by it". How do y'all rule as "designate"? Does the cleric pick those unaffected by name or by sight? Would "my party" or "my allies" qualify as an appropriate designation, or do they have to pick individual creatures?
.

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It says you can see. So imo you have to designate by sight. i.e. that figure there, that one there, that one there. I would not allow you to say 'my party' or 'allies' or 'good aligned' or such.

Now, what I would do if I were the cleric is not designate anyone except myself (and any allies I am 100% certain about). Let your allies take they damage, they can handle it. The drones can't. It's the same idea as dropping a fireball into the middle of melee.

Keep it simple. Let the cleric player say it however he likes. If he says it doesn't affect his friends and allies but does affect his enemies, believe him. It's not supposed to be a gotcha like a Wish spell or something.

'Designate' just means 'specify' - it can be by pointing, naming verbally or in writing, or even just throwing a tin of paint over something. All that matters is that you know what his intentions are.

Yeah, it means he can designate the real PCs by naming them and the fake PCs get hit. Nice one.

What [MENTION=6804070]LordEntrails[/MENTION] said. If the spell said "affects enemies" I'd let it affect all the drones without having to identify them but this says you must "designate creatures you can see" so I reckon you have to specifically select who gets affected and who doesn't. Having said that, I'd let the cleric make an intelligence check to correctly identify who's who as an action.

I don't see how a Changeling Drone is CR 3. It has 16 HP. It looks more like a CR 1/2 creature. It has no ranged attack whatsoever.

It's best tactic is to run away. Then go hire some CR 1/2 Scouts that also have 16 HP and have them fire longbows from maximum range.

I see nothing wrong with a 3rd level spelling chewing up CR 1/2 creatures. Though, even then, the spell does 3d8 damage. That's an average of 13.5 on a failed save and 6.75 on a successful save. The drones in groups of 3 have advantage on Wisdom saves at +1. The cleric probably has a DC of 15. The drones should be saving 58% of the time. So if they were at full health none would die and most would be scratched.

It's impossible for the drone to wipe out every single drone in one round if they are at full HP. If the drones wanted to, they could probably swarm the cleric (they can fly so can fly around the cleric) and attack enough times to cause the cleric to fail a concentration check.

guachi said:

I don't see how a Changeling Drone is CR 3. It has 16 HP. It looks more like a CR 1/2 creature. It has no ranged attack whatsoever.

It's best tactic is to run away. Then go hire some CR 1/2 Scouts that also have 16 HP and have them fire longbows from maximum range.

I see nothing wrong with a 3rd level spelling chewing up CR 1/2 creatures. Though, even then, the spell does 3d8 damage. That's an average of 13.5 on a failed save and 6.75 on a successful save. The drones in groups of 3 have advantage on Wisdom saves at +1. The cleric probably has a DC of 15. The drones should be saving 58% of the time. So if they were at full health none would die and most would be scratched.

It's impossible for the drone to wipe out every single drone in one round if they are at full HP. If the drones wanted to, they could probably swarm the cleric (they can fly so can fly around the cleric) and attack enough times to cause the cleric to fail a concentration check.

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Their original HP was 33, but I reduced it for this specific fight to balance the quantity. There are fifteen of them - three for each of the characters. I did forget to reduce their CR, though. Thanks for catching that.

TheNoremac42 said:

Their original HP was 33, but I reduced it for this specific fight to balance the quantity. There are fifteen of them - three for each of the characters. I did forget to reduce their CR, though. Thanks for catching that.

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Even with 33 HP, seems like they are CR 1 at most.

transtemporal said:

What @LordEntrails said. If the spell said "affects enemies" I'd let it affect all the drones without having to identify them but this says you must "designate creatures you can see" so I reckon you have to specifically select who gets affected and who doesn't. Having said that, I'd let the cleric make an intelligence check to correctly identify who's who as an action.

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I would pretty much agree with this.

Harzel said:

Even with 33 HP, seems like they are CR 1 at most.

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They were patterned after a combination of the Thri-kreen and Doppelganger. The Thri-kreen by itself has a CR of 1, but these Changelings have additional traits that improve their stealth and give them a sort of enhanced Pack Tactics ability. I thought the increase in CR was appropriate.

I would let the spell work as written. I see Fred, Bob, and Tom. I also see Fred clone, Bob clone, and Tom clone, but I explicitly knew the difference because I walked in with Fred, Bob, and Tom. They didn't teleport to a new location when the drones changed into copies of them. The spell is magic. It can tell the difference.

Now, if I make a mistake as the Cleric PC, that's a different story. If I accidentally pick Bob clone instead of Bob because my vision was impaired for a moment, so be it.