Beheaded Form. When created, a death's head takes one of three forms: Aberrant Head, Gnashing Head, or Petrifying Head. This form determines the creature's attack.
Unusual Nature. The death's head doesn't require air, food, drink, or sleep.
Gnashing Bite (Gnashing Head Only). Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit:4 (1d6 + 1) piercing damage plus 7 (2d6) necrotic damage.
Mind-Bending Bite (Aberrant Head Only). Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit:4 (1d6 + 1) piercing damage plus 5 (1d10) necrotic damage, and the target must succeed on a DC 10 Intelligence saving throw or it can't take a reaction until the end of its next turn. Moreover, on its next turn, the target must choose whether it gets a move, an action, or a bonus action; it gets only one of the three.
Petrifying Bite (Petrifying Head Only). Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit:3 (1d4 + 1) piercing damage, and the target must succeed on a DC 10 Constitution saving throw or be restrained as it begins to turn to stone. The target must repeat the saving throw at the end of its next turn. On a success, the effect ends. On a failure, the target is petrified for 10 minutes.
A death's head is a disembodied, flying head. The type of creature one of these grotesque undead originated from determines how it terrorizes it prey. A death's head that arises from a person or animal swoops down to rip apart victims with its gnashing teeth. One with the head of monster like a nothic or medusa, though, retains a measure of the power it had in life and can befuddle the minds or petrify the bodies of its victims.