Hello just here to yaba on :D
My Shadow The Hedgehog Head canons:
1- He is a bookworm. I got inspiration from other people on this and I totally believe it too. I can see him reading a book on a true story or on medieval monarchy and having a huge bookshelf.
2- He is deathly afraid of spiders. This is my own head canon. Hear me out, like on the ark they wouldn't have spiders, would they? Like he sees the 8-legged creature crawling on the roof and get freaked out. He downright believes he has at least 5 cans of bug poison and uses it all on spiders. And Infront of other people when he sees a spider he freezes up, trying to seem calm but genuinely terrified. And I feel Rouge would know about this fear and use it against him lmao.
3- He studies astronomy. My own head canon. I believe this in both the movie and the main franchise since Maria loved Stars so much, studying them makes him feel closer to her.
Yeah, those are my Shadow head canons lol. If you're reading this, please comment so I don't feel like I'm talking to myself :'D