D&D 5E When a Lightning Bolt spell met the floor ...

[Nickolaidas]

Okay, so I've been DMing 5E with my brother, my sister-in-law and my kid nephew.

I ambushed their group with some Dragonborn cultists of Blue Dragon heritage. At some point, my brother's paladin was surrounded by a Maw Demon on his back, one Dragonborn cultist to his front, and one Dragonborn cultist to his left.

Important note: we play with minis (the entire map and the miniatures are on my photoshop shown in the TV and I move the miniatures with my Bluetooth mouse as they wish - kinda like a video game, actually). The three enemies are literally next to the paladin from three sides (melee distance).

In the map grid, it was like this:

. M
CPE
. C

P=Paladin
M=Maw Demon
C= Cultist
E=Empty Block

When the cultists' turn came, I announced that they both fired their lightning breath weapon (which is a 5x40 ft line, if I recall), aiming diagonally at my big bro's paladin (basically, they aimed at his legs, so that the lightning bolts would hit only the 5ft square where the paladin stood - so that the cultist in the front wouldn't hit the Maw demon with his breath - since the Maw Demon was positioned behind the paladin).

My brother got annoyed and told me that the lightning bolt of the front cultist couldn't hit him and NOT hit the Maw Demon as well because the bolt is a straight line. I told him that they aimed their lightning breath line diagonally to the floor where his paladin stood (I guess at a 45' degree angle). He said that the lightning bolt should still 'bounce' when it hit the floor and hit the Maw Demon anyway (by rising at a 45' degree like the ball in Pong does when it hits a wall). He claimed that my logic makes the lightning bolt a cheap spell where it can be used in close quarters (literally next to an opponent) to hit a single foe without endangering any ally even though they're standing next to the assailant and / or the victim.

I did some searching on the net and I couldn't find anyone conveniently explaining what happens to a lightning bolt (either breath or spell) when it hits a wall, a ceiling or the floor. Does it disperse harmlessly? Does it bounce? If it bounces, does the caster control where the line goes next? And if hit someone next to a wall, and then the lightning bolt bounces off the wall and hits the same victim again, does the caster roll again for damage even though the target got hit 2 seconds ago?

Please share your thoughts on this, and tell me if my 'aim at his legs' logic was wrong.

 

[alienux]

There are no "called shots" in D&D 5E, so aiming at specific areas of the body lower down isn't really a thing, unless used just for flavor. Lightning Breath reads:

A stroke of lightning forming a line 20 feet long and 5
feet wide. Each creature in the line must make a Dexterity saving
throw.

The spell Lightning Bolt, in the PHB, is almost exactly the same, except it is 100 feet long instead of 20. In either case, it clearly hits any creature in that line. So each creature directly behind the target up to the appropriate distance needs to make a saving throw and take damage as necessary.

 

[S'mon]

I think in 5e lightning bolts don't bounce. They did in 1e.

However lightning bolt is an area effect spell with a 5' wide line. if I as GM allowed or used "I aim at his legs" then at the very least I would give advantage on the DEX save - and probably no damage on a save; the half damage assumes an area too wide to easily avoid.

However #2 - in 5e there is no reason why the cultists couldn't first move 5' sideways before lightning bolting so as to get a clear shot. So this issue should not have arisen.

 

[ad_hoc]

I wouldn't feel great about that either. Worse for a DM, but I would also not enjoy it if another player tried to pull that.

It's technically in the rules but I feel that when we are getting into degrees that is fiddly and gamey. It doesn't capture the mood I want out of my D&D.

 

[UngeheuerLich]

Ähm. If you can shopt diagonally on the x-y axis you can also do so on the z-axis. Of course you can shopt downwards. But I would also either give the first target advantage or allow the maw demon to save with advantage. It is quite difficult to aim that good. I might have you make a spell attack vs DC 20 to exactly hit only the person in front of you.

 

[LordEntrails]

Any tactic you allow the NPCs to use you better plan on allowing the PCs to use. And in my experience, tactics such as these are MUCH more powerful in the hands of the PCs then they ever will in in NPCs.

So, leaving the ruling in place that you made, if I have learned anything in 40 years of playing, you will regret it.

"Playing" around the edges of the rules is dangerous.

 

[TallIan]

My argument against targeting the pall'y legs would be that you target a square with an AoE. So in this case, you're aiming at the square (cube really) below the pall'y

A square grid system doesn't cope will with diagonals, so you really should give the target some kind of advantage (not the game mechanic) for being in a square only partially covered by the AoE effect (bonus to save, no damage on a save, half damage, Advantage (the game mechanic) are all possibilities) since you are essentially increasing the AoE.

These are the possibilities that I see (L is for Line; X are unaffected squares)

LPXX
XLXX
XXLX
XXXL

LLLL
XXX

LXXX
LXXX
LXXX
LXXX

Sp hitting the Pall'y in the case of a diagonal seems like you're extending the AoE

 

[Shiroiken]

In AD&D, lighting bolts would bounce off the walls (back at the caster in 1E, using geometry in 2E) unless the wall was a conductor. Like most spells in 5E, everything has been simplified, so this is entirely a DM call. I would suggest if you do have the lightning bounce, that you only deal regular damage to each creature in the area, even if a creature would be struck more than once (perhaps granting disadvantage instead).

If you are playing on a grid, and using the grid rules, then you couldn't aim the lightning down to miss the maw demon unless you were 5' up in the air (so that the line could follow the z axis). Arguably, you could drop prone, and cast it upwards.

If you are doing theater of the mind, I could see the argument made, but would grant half damage on a failed save, and no damage on a success for the paladin (and possibly advantage as well).

As someone else has pointed out, in this example the cultist could have simply moved to a diagonal space, avoiding the argument entirely.

 

[Nickolaidas]

There are no "called shots" in D&D 5E, so aiming at specific areas of the body lower down isn't really a thing, unless used just for flavor. Lightning Breath reads:

A stroke of lightning forming a line 20 feet long and 5
feet wide. Each creature in the line must make a Dexterity saving
throw.

The spell Lightning Bolt, in the PHB, is almost exactly the same, except it is 100 feet long instead of 20. In either case, it clearly hits any creature in that line. So each creature directly behind the target up to the appropriate distance needs to make a saving throw and take damage as necessary.​

So the only way a diagonal line of lightning could've hit the paladin and only the paladin would be for the attacker to be at least 5ft above the ground? Like, for example, a Young Blue Dragon firing his breath at a party of 4 adventurers (with them having formed a square formation) while flying 5ft above the ground and be next to the paladin?

PFD
CT

P=Paladin
F=Fighter
C=Cleric
T=Thief
D=Young Blue Dragon (who is also 5ft in the air)​

In AD&D, lighting bolts would bounce off the walls (back at the caster in 1E, using geometry in 2E) unless the wall was a conductor. Like most spells in 5E, everything has been simplified, so this is entirely a DM call. I would suggest if you do have the lightning bounce, that you only deal regular damage to each creature in the area, even if a creature would be struck more than once (perhaps granting disadvantage instead).

If you are playing on a grid, and using the grid rules, then you couldn't aim the lightning down to miss the maw demon unless you were 5' up in the air (so that the line could follow the z axis). Arguably, you could drop prone, and cast it upwards.

If you are doing theater of the mind, I could see the argument made, but would grant half damage on a failed save, and no damage on a success for the paladin (and possibly advantage as well).

As someone else has pointed out, in this example the cultist could have simply moved to a diagonal space, avoiding the argument entirely.

I did that in the end, but I gave the paladin an Attack of Opportunity (which I wanted to avoid).

 

[S'mon]

I did that in the end, but I gave the paladin an Attack of Opportunity (which I wanted to avoid).

You don't get an opp att for that in 3e 4e or 5e, and 1e-2e didn't have opp atts per se.