Disturbing cartoon on Adult Swim

Hi, late response I know! I'm not sure if its been entirely ruled out, but I was obsessed with Superjail in high school [I mean obsessedddd. I knew every episode by heart] It sounds like there was a gap between the shot of the island and the chainsaw scene which sounds a lot like the Lord Stingray Crash Party episode, complete with the opening on an island with a palm tree. It's also worth keeping in mind false memories, bc I was convinced you were looking for this episode but the scene I remembered as someone getting killed with a chainsaw was actually a machete. If it's not this episode, I'm still pretty convinced it was likely from Superjail. My partner and I are actually meaning to watch every episode together soon for nostalgias sake, so I'll keep my eyes peeled for anything like you described !