D&D 5E Optimized Giant Frog?

[faria]

So I have a character idea that I love, but I'm not sure what the ideal way to build it is.

Basically, pick a small race, ride a Giant Frog, cast Enlarge/Reduce to shrink enemies, and swallow them.

For reference:
GIANT FROG
Medium beast, unaligned
Armor Class 11Hit Points 18 (4d8)Speed 30ft., swim 30 ft.
STR12 (+1)DEX13 (+1)CON11 (+0) INT 2 (-4) WIS 10 (+0) CHA 3 (-4)
Skills Perception +2, Stealth +3
Senses darkvision 30ft., passive Perception 12
Languages -
Challenge 1/4 (50 XP)
Amphibious. The frog can breathe air and water.
Standing Leap. The frog's long jump is up to 20 feet and itshigh jump is up to 10 feet, with or without a running start.
ACTIONS
Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target.Hit: 4 (1d6 + 1) piercing damage, and the target is grappled(escape DC 11). Until this grapple ends, the target is restrained,and the frog can't bite another target.
Swallow. The frog makes one bite attack against a Small orsmaller target it is grappling. If the attack hits, the target isswallowed, and the grapple ends. The swallowed target isblinded and restrained, it has total cover against attacks andother effects outside the frog, and it takes 5 (2d4) acid damageat the start of each of the frog's turns. The frog can have onlyone target swallowed at a time.If the frog dies, a swallowed creature is no longer restrainedby it and can escape from the corpse using 5 feet of movement,exiting prone.

There are 2 ways to get a Giant Frog mount: Paladin's Find Steed spell, and Beastmaster Ranger's Animal Companion.
There are 2 ways to get Enlarge/Reduce: Sorcerer or Wizard.
Note: A level 6 Lore Bard can steal both Find Steed and Enlarge/Reduce...

I think a Beastmaster is the most optimal main class because of the scaling pet HP. For subclass, Divination Wizard pops out because of Portent, but Wild Sorcerers get Bend Luck which would help with enemy saves but requires more subclass levels invested. It's too bad Haste doesn't stack with Enlarge/Reduce (both are concentration) or the extra Sorcerer levels would definitely win out...

What's the most optimal combo to make this happen? What's the best Small size class for this? Maybe Forest Gnome for the +2 INT if Beastmaster/DivWiz? Kobold for Pack Tactics since Bite and Swallow are just attacks that benefit from advantage? What's the level by level breakdown here?

 

[Corran21]

I prefer find steed, because if the frog dies, you can simply cast the spell to bring it back. Safer option.
Moreover, with find steed, you can share buffs with the frog, such as armor of agathys (if you grab it as one of your magical secrets). This will help a lot with the frog's survivability (there must be other (non-)concentration good buffs as well).

ps: I wonder, if you cast enlarge on the frog, would it be able to swallow medium creatures? It seems logical but it might fall under DM's discretion as RAW might not cover it. This would seriously boost this strategy (you would have to play a medium sized race in this case, in order to mount the frog). I am assuming you think this is not the case, and that is why you went with the reduce version of enlarge/reduce.

 

[kalani]

By RAW - the Giant Frog's "Swallow" feature isn't affected by changes in the Frog's size. You could enlarge/shrink the frog and it would still only be able to swallow small (or smaller) creatures. Heck, you could give it a potion of Giant Size from SKT, and it still would be limited to small creatures.

 

[faria]

Yeah i'm sticking to RAW, hence why I use Reduce on the enemy instead of Enlarge on my frog.

Find Steed let's you resummon it with a spell slot, but I don't want it dying in the first place. I think Beastmaster is preferable here because it scales the companion's HP. I recently finished a HotDQ campaign and those AoE dragon breaths are no joke. They'd take out a low HP mount every time even if it resisted for half damage.

Is going for Find Steed worth the risk? I could take the Mounted Combatant feat to mitigate/negate some of those AoEs... I'm still afraid of it dying though.

Then again, I'm guessing Swallow won't work on certain bosses anyway (many are Large size or bigger), so maybe I shouldn't worry too much about BBEG AoEs killing it and go with Find Steed? Help =\