This particular caterpillar isn't actually a real king (I know! Pretty shocking!) But whatever you do DON'T tell him that, other than it upsetting him, if he isn't king, who is going to make awesome royal decrees like 'one must have jelly and custard after every meal including breakfast'?!.
So how did this caterpillar become so royal? Well he once found a crown and decided to wear it for the day. When he went shopping (for jam, crutons and other normal caterpillar food) he was presented with a free jar of pickle for being all king like. (Well what else do you offer a king?) He decided this was pretty awesome and never removed the crown from his green head.
If I ever meet a king I'm totally going to present him pickle OR maybe a swan?! Guess it depends on what's handy at the time. (Most likey the swan then.)
Decrees - It's great to make up your own rules, why not try it yourself today?!
Losing his crown - Not only does it mean he doesn't get free treats, his head is vulnerable to sun burn, oh no!