World Book Day panic

[EnglishHamlet]

Please help!
12 year old boy at secondary school.
School announced on Monday that they want kids to dress up as book characters for World Book Day.
I thought WBD was on Friday so I was planning to sort this out tomorrow, as I have the day off work.
To my horror, I've literally just found out they have to go in dressed up tomorrow!!! DS's school are doing WBD tomorrow!!!
Help!
What on earth can I dress DS as?
To make it more complicated, he now wants a 'cool' look, understated, low key, as he says he'd get laughed out of secondary school if he went in dressed as Harry Potter.
It's 8pm, I'm tired, and I'm really panicking!

Some ideas for characters in everyday clothes here…or something that might fit in with clothes he’d be happy to wear
https://sevenoaksbookshop.co.uk/teen-boys/

or what about Stanley from Holes by Louis Sachar - not sure if they still do but they used to read it at Key Stage 3. Not exactly seasonal but shorts/t-shirt and baseball cap should work

OP you have probably hot an idea now but what about guiness book of world records. Just regular clothes, edging on smarter, with a stop watch and clipboard/book. Maybe a calculator. He would be an official judge. If you have a lanyard knocking around use that or make one with string.

Dressing gown and towel around the neck - hitchhikers guide to the galaxy. Extra point if you have a battered bag with a couple of old dog eared scripts in it plus a kindle with don't panic sticks on it - Ford Prefect

Thanks so much everyone for all your thoughts and ideas!
He went in as Percy, as soon as I looked at images of Percy online I thought it was brilliant as he has exactly the same hair! So we found an orange t shirt, a checked shirt to wear over the top, a beaded necklace, and he quickly knocked up a cut out lightening bolt and sprayed it gold with a can of gold spray paint I had at the back of the garage!
Ta da!
He was really pleased, as he still got to wear his own jeans and trainers and kept his hair the same, so didn't feel too 'fancy dress' which is just right for his age.
Thank you so much everyone!!🤗

Sounds perfect, glad you got sorted

Sounds great, hope he had a lovely day.