Angry Cryogonals falling from the skies while tied to Combees and Shapedos with tinsel, actually. Though I've no doubt it'd be useful in any cave.

[One of the main advantages of being sedentary is not dealing with exploding Gravellers, he's found.]

As it happens, Earthquake is one of my reusable TMs. That would ensure it'd know a strong attack immediately... Unless it needs to evolve first, but that's a minor issue. Besides, they surely can learn Ice Beam; that would handily counter most Grass-types.