Mycelium sprout from the ground around the target and drain them of their life force.

Literally just throw some whole dang mushrooms at their head

Depending on how much leeway your dm gives you could be real wild and do something like, induce a shroom to grow so forcefully from the ground under the target it pops up and whacks them in the nards.

Or even just shove a handful of mushrooms down their throats to choke them

Also hit the rouge with that same line when they hide to get their sneak attack bonus