It's hard to believe but there was once a time when imaginary friends were not the exclusive right of well-spoken children who had recently moved into old, creepy houses. Like gurgling, clutching a bottle and filling your nappy, talking to yourself is one of those things that is acceptable (almost cutesy, even) when you're a little kid but significantly less so when you're approaching your forties. Likewise, there's only so many times you can blame a broken vase on 'you know who' before your parents cart you off to the child psychologist. In short, 'funny; haha' can quickly become 'funny; strange'. Which is presumably why horror is so reluctant to let it go. The imaginary friend is the saviour of the only child, the fruits of an over-active imagination, the conscience personified. We can't all have a sharp-suited cricket on our shoulder, but if a Stone Age simpleton like Fred Flintstone can have a small green spaceman constantly berating him, then why can't you or I be granted an invisible companion? It could be a volleyball with a crudely-drawn face or it could be a giant rabbit (scary mask optional). Below are ten of the most incredible, insane and insufferable imaginary friends in cinema. Oh, and before you start, Lord Fizzlerocket (the fellow who lives in my right ear) reminds you to look out for spoilers.