How do you kill an onion druid without looking like a jackass

How do you kill an onion druid without looking like a jackass

Avoid using slashing or piercing weapons.
Barring that, goggles.

Now I really want to play an Onion Druid.

Disintegrate.

There's probably other "dies on 0" effects you can hand out to your monsters I can't think of.

Let him fry.

If you're doing decent damage you should be making slow progress while the druid basically can only use wild shape and move around. Otherwise basically anything that isn't direct damage still would work fine

Wound a few times and leave in a dry place

Lure him into a giant cauldron filled with stew that needs onion.

A what?

Ignore him and kill all his friends first.

A moon druid, using wildshape to produce stack after stack of hit points.

Why onion? Layers?

Yes. At maximum potential they can endlessly put up a new wall of hit points.

Correct me if I'm wrong, but isn't that only a thing at level 20?
Until then moon druids only get 2 uses of wildshape every short rest, no?
I'm also assuming 5e, since I'm not too well versed in 3.5

Onions have layers

hire an ogre warrior

The fact that you WANT to kill a PC already makes you a jackass, so you're fucked from the get to go.

It's not uncommon for a DM to create a boss or antagonist using the same template as a PC.

1) Cone of cold or any other chilling effects
2) Hack and slash like Conan on an acid trip
3) Throw into a pot and make soup out of it's remains
4) Serve the soup at a nearby orphanage

Civic duty done.

Unfortunately, acting like a jackass is the best option since onion druids can't stand them. Compare their fighting style to a cake, which also has layers, or offer to follow them on their adventures when they just want to be left alone. If all else fails, make them waffles.

Or you could just stay out of their swamp

Chew gum while fighting them, it works wonders.

Put them in the fridge for a while before taking your blade to them.

Or a donkey to pierce through all of them.

I giggled at this

Layer by layer

Knock him/her/it out. Flour him/her/it up, put oil in a big-ass vat, and sink him/her/it in until it turns a nice golden brown.

The smell would be otherworldly.

I'm hungry just thinking about it.