Incorporeal Movement. The wraith can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Sunlight Sensitivity. While in sunlight, the wraith has disadvantage on attack rolls, as well as on Wisdom Perception checks that rely on sight.

Amorphous. The pudding can move through a space as narrow as 1 inch wide without squeezing.

Corrosive Form. A creature that touches the pudding or hits it with a melee attack while within 5 feet of it takes 6 (1d10) necrotic damage. Any nonmagical weapon made of metal or wood that hits the pudding corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed.

Nonmagical ammunition made of metal or wood that hits the pudding is destroyed after dealing damage.

The pudding can eat through 2-inch-thick, nonmagical wood or metal in 1 round.

Life Drain. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 21 (4d10 + 4) necrotic damage. The target must succeed on a DC 14 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.

Create Specter. The wraith targets a humanoid within 10 feet of it that has been dead for no longer than 1 minute and died violently. The target's spirit rises as a specter in the space of its corpse or in the nearest unoccupied space. The specter is under the wraith's control. The wraith can have no more than seven specters under its control at one time.

Pseudopod. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) bludgeoning damage plus 18 (4d8) necrotic damage. In addition, nonmagical armor worn by the target is partly dissolved and takes a permanent and cumulative −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.

Split. When a pudding that is Medium or larger is subjected to lightning or slashing damage, it splits into two new puddings if it has at least 10 hit points. Each new pudding has hit points equal to half the original pudding's, rounded down. New puddings are one size smaller than the original pudding.