My frined is crashing everyone near him

my friend has found this hat, he doesnt know what hat. He took it on and then he crashed everyone near him, and every time he tries to log in he cant and all around him crashes

Edit: its the anchient mask, from Botania, and he took it on in the curio slot.

Quote from Josh

Try deleting his playerdata:

Delete someones player file – Aternos

Does that also remove stuff from curios inventory?

I cant find his UUID when he is logging on https://mclo.gs/DNhXTh5

where did you find that? My other friend also weared the hat, and i want to do some testing

thank you so much