Willy had a crocodile
It snapped in the morning
It snapped in the night
It snapped once too many times and snapped off his...

Willy had a ...etc. etc (repeat first verse)

(ed: Becky says this song works better if the name is changed to Shirley - but I can't see how! She also said it was part of a similar handclapping song - but I can't find the original so Becky, if you're out there. please remind me?)