I was playing in one of my creative worlds when I suddenly noticed my rotating armour stand I had made earlier had a super weird skin. I put down another armour stand and the skin changed each time I put one down it changed to something new - an invisible armour stand with an elytra coloured arm and leg, a one with every block texture on, a pink one that looked like a pig texture on the armour stand, etc

I only managed to get the elytra and the block one, I couldn't find the pig one again to take a screenshot.