Go Ahead. Admit It Was Lava.
I so did this. What is funny is that I remember the genuine panic I would feel if slipped off the couch and into the lava. Thankfully I never died from the lava. My friends and I would say "Oh, you landed on a log! Hurry get on the couch before the log sinks." Or if it wasn't a log it would be a bird who swooped under me. Amazingly I never died from lava burns. There was always some fantastic escape from the fiery doom. Which is fortunate because I fell off the couches a lot during these games.