Any time a creature strikes the tarry demodand with a non-natural melee weapon, the attacker must succeed on a DC 16 Strength saving throw or the weapon becomes stuck to the demodand's body. If the weapon's wielder can't or won't let go of the weapon, the wielder is grappled while the weapon is stuck. While stuck, the weapon can't be used. A creature can pull the weapon free by taking an action to make a DC 16 Strength check and succeeding. Doing so, however, subjects it to an opportunity attack by the tarry demodand.