Sack Horror (5e Creature)
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Medium undead, chaotic evil
Skills Intimidation +1, Stealth +3
Death Burst. When the horror dies, its body transforms into purple fog over a 10-foot radius. A creature that starts its turn inside the fog or moves into it for the first time on its turn must succeed on a DC 13 Constitution saving throw or be poisoned until the end of its next turn. A creature inside the fog cannot breathe. Undead, constructs, fiends and creatures that do not breathe are immune to this effect. The fog dissipates after 5 minutes or a strong gust of wind blows it away.
Turn Resistance. The horror has advantage on saving throws against any effect that turns undead.
Multiattack. The horror makes two attacks with its claws.
Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) slashing damage.
Sack horrors are lesser cousins of masked horrors, with sacks where their heads should be that appear to be empty, as they contort in ways that would be impossible if the creature had a head. Two holes in the sack, positioned like eyeholes, reveal red orbs burning with hatred, and another hole that would appear to be the mouth, always looks mournful, as if they regret becoming undead and being forced to kill other creatures. Sack horrors look exceedingly similar to masked horrors, except they lack a mask. Sack horrors are empowered by these sacks, charged with foul energy through rituals, though the sack is a weaker receptacle than a mask for this energy. They slash at their foes with vicious claws, and when they die, their bodies become toxic fog, leaving only the sack behind.
Undead Nature. A sack horror doesn't require air, food, drink, or sleep.