rtkermit is making some sort of a cobblestone thing, but what's much more interesting is this poor mob spawned way up there. Think about the conversation in his head:

"And.....POW I exist. Whassup world? Where's some players for me to attack! Where's a wall to climb? Hmm. This is unfortunate. This is the worst place to spawn ever. I see you down there kermit and surf and hostile, but if I jump down, I'll die. Well...this sucks."

BustaCapps has been building Cappsylvania, and nearby he found an almost-surface level Spider dungeon. A normal person would just kill it, or make a trap. Busta built a coliseum. Naturally. This is someone (possibly freddiekclarke) getting obliterated in the coliseum.