I realize that the Devour Ally bonus action is unclear. I thought the Muck Monster would regain 3 x the CR of the creature it ate. But I think it just regains 3x it's own CR, so 12 hit points for each ally it ate. If I make Muck Spawn I'll probably make the amount the Muck Monster regains from eating them equal to their hit points, so 12 seems about right. We'll see. I'm inspired by a horrific video I saw of a mother crab going to town on her newly hatched offspring. Brrrr...yuck!
Fetid Demise. When the muck monster is reduced to 0 hit points, it releases a cloud of poisonous gas. Each creature within 30 feet of it must succeed on a DC 13 Constitution saving throw or take 4 (1d8) poison damage.
Actions
Multiattack. The muck monster makes two attacks.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 17 (3d8 + 4) piercing damage.
Mucous Spray. Ranged Weapon Attack: +6 to hit, range 20/60 ft., one target. Hit: 17 (3d8 + 4) acid damage.
Bonus Actions
Devour Ally (Bonus Action). This creature swallows an allied creature who is within 5 feet of this creature and is smaller. This creature regains CR × 3 hit points and the devoured ally is reduced to 0 hit points.
I realize that the Devour Ally bonus action is unclear. I thought the Muck Monster would regain 3 x the CR of the creature it ate. But I think it just regains 3x it's own CR, so 12 hit points for each ally it ate. If I make Muck Spawn I'll probably make the amount the Muck Monster regains from eating them equal to their hit points, so 12 seems about right. We'll see. I'm inspired by a horrific video I saw of a mother crab going to town on her newly hatched offspring. Brrrr...yuck!
Alt text for the stat block:
Malodorous Muck Monster
Large monstrosity, unaligned
Armor Class 14
Hit Points 85 (10d10 + 30)
Speed 30 ft., fly 60 ft., swim 30 ft.
STR
11 (+0)
DEX
18 (+4)
CON
17 (+3)
INT
8 (-1)
WIS
11 (+0)
CHA
7 (-2)
Skills Stealth +6
Senses passive Perception 10
Languages —
Challenge 4 (1,100 XP)
Fetid Demise. When the muck monster is reduced to 0 hit points, it releases a cloud of poisonous gas. Each creature within 30 feet of it must succeed on a DC 13 Constitution saving throw or take 4 (1d8) poison damage.
Actions
Multiattack. The muck monster makes two attacks.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 17 (3d8 + 4) piercing damage.
Mucous Spray. Ranged Weapon Attack: +6 to hit, range 20/60 ft., one target. Hit: 17 (3d8 + 4) acid damage.
Bonus Actions
Devour Ally (Bonus Action). This creature swallows an allied creature who is within 5 feet of this creature and is smaller. This creature regains CR × 3 hit points and the devoured ally is reduced to 0 hit points.