Enjoyment from infant-related things. Pretending to be a baby, wearing diapers (see diaper lover, speaking like a child (ie "I sowwy"), sleeping in a crib. Wide range of things, but all infant-related

Note that this is interest in the trappings/behaviour of youth, not sexual interest in the youth themselves (that's a pedophile)

A person or people that purposefully causes chaos or mischief within a group for the sake of entertainment.