Based off this video because I cannot stop laughing
It had started out as a simple enough dare, Dean and Cas would each get a total of 3 tries per person to try and “kill” the other by telling the other that “the floor is lava.” They would then have five seconds before they had to find a way to get off the ground and scream that the floor was lava to any unsuspecting passerby if there were anyway. There was no prize, not really. Dean just really wanted to beat Cas at something, and Cas didn’t mind if he got bragging rights.
Cas had been first, during a walk in the park between their two college classes on campus. “The floor is lava,” he’d casually said. Dean had not understood until he did, and at which point he only had 3 seconds left and nothing that he could use to get off the ground. Nothing, except, for a trashcan just up the trail. He’d made it with one second to spare.
“The floor is lava!” Dean screamed triumphantly, balancing precariously on the poor trashcan below him. He had managed to get into a crouch before the inevitable happened––when Dean went to get down back onto the ground and rejoin Cas he slipped and wound up wedging his butt straight into the trashcan. Castiel wouldn’t let him forget it for a week.
The next turn had been Dean’s, choosing to wait until Cas and he were on a grocery run to enact his plan.
“Hey, Cas,” he called the other’s attention while they were in the toilet paper aisle.
“The floor is lava.”