I guess there is a first time for everything
I've seen my fair share of hackers, mainly killers in this game (since I mainly play survivor), but wow... I have never seen someone bring a mori. They made us scream the entire game too, just randomly and then used dead hard when they did not have dead hard.

Comments
It didn't turn over for us survivors. So I am assuming it didn't turn over for them too, just like they can't see when we throw 'shroud of binding' offerings.
Killer probably thought it was binding or union, y'know, reasonable offerings, lol
Perhaps he was expecting survivors to not solve pinheads box and wanted to get a point across.