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.

Actions

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.

Death's Head