Ok. So I've slightly messed up. Never never never assume you can get a Halloween costume in the sales after Halloween.
DS aged 3 wants to be a monster. Actually he wants to be a green monster. I've got a scary green and white mask which he's happy with. In fact, I thought I might have got away with it until he told me at bedtime that he wants a 'scary tummy and scary legs' too. Bugger.
I'm currently thinking about cutting off and fraying some old trousers (Frankenstein style) and teaming with a green t-shirt. Please tell me someone has a better idea?!
... and I should mention that the party is at 3pm tomorrow.
Looking on the bright side, I made some spider cakes!