That happens in Between Studies, towards the end. An anon tells a Marisa their ripped-up hat will restore when it falls on their head, and it does.
He then later exploits this by taking out an eye from a Marisa and Reimu, telling them they'll only get them back if they will for him to do well on his studies, and presumably he does.
Good thing Yukkuri are too stupid to realise they can do shit like this, or comics would take one hell of a different turn.