If you manage to stun Snarbolax right before he dives underground to do his spine dash it will cause him to still spawn spikes once he comes back above ground. While he is still stunned and vulnerable, you cannot safely get close enough to melee him as he is still spewing out spikes (and in great number) all around him.

http://i130.photobucket.com/albums/p262/DirtTB/Spiral%20Knights/2011-06-...
He covered himself again by the time I took the screenshot, but this is what it's like. He can still move and bite you while this is going on. I'm assuming this can continue until he goes back underground. It has only happened to me twice, but it can cause some unnecessary damage.