Once upon a time there were 3 trolls who lived under a bridge: Mr Troll, Mrs Troll, and little baby Troll. Every morning they would eat each other up for breakfast.
One morning, after a particularly fine feast on the other members of his family, Mr Troll sat staring out from under the bridge with a thoughtful expression on his face. “You know”, he said, picking a bit of Mrs Troll out from between his teeth, “I’m not entirely sure that gobbling each other up every morning is the right thing to do.” Mrs Troll rolled her eyes and turned back to do the washing up. She felt that Mr Troll was doing entirely too much thinking these days.
Baby Troll let out a long, growling belch and then said, “Well Dad, our behaviour certainly sets up something of an ontological conundrum. Do you think we should consider eating goats instead?”