'Caitlin runs on food.'

Earlier, just sitting here with Ben printing off some Thomas and Friends activity and colouring pages we came across a picture of 'Mavis'. Ben quickly said 'That's Mavis. Mavis runs on coal.' Then he paused and said 'Caitlin doesn't run on coal. Caitlin runs on food. Caitlin runs on baby milk.'

Totally cracked me up.