Equipped creature has deathtouch

Whenever equipped creature deals combat damage to a player, put a -1/-1 counter on each creature they control. Then destroy target non-creature permanent that player controls.

At the beginning of your upkeep, if 035, Possessive Mask isn't equipped to a creature, put a -1/-1 counter on each creature you control, then sacrifice a noncreature permanent.

At the beginning of your endstep, put a -1/-1 counter on equipped creature.

Equip {3}