The thing hurtling down the tunnel was definitely a shambling mound, but what was it doing underground? The lack of light had done a number on it and all of its foliage was browning. In this condition, perhaps fire would work well after all.
When Alber’s firebolt hit the creature, however, it seemed to grow as it rushed toward them.
Hungry Mold. This strain of brown mold comes into existence at the intersection of magic and need for heat. When a heat source starts to die where brown mold has previously thrived and the right powers are present for a magical evolution, brown mounds may begin to emigrate from the dying heat source to hunt other warm things.
Self Preservation. When a brown mound is about to be destroyed, it may collapse voluntarily in a feint of death in hopes its enemy will pass it by and allow it to live to hunt another day.
Large plant, unaligned
Armor Class: 15 (natural armor)
Hit Points: 136 (16d10+48)
Speed: 25 ft.
|18 (+4)||8 (-1)||16 (+3)||5 (-3)||10 (+0)||5 (-3)|
Skills: Stealth +2
Damage Resistances: lightning, poison
Damage Immunities: fire
Damage Vulnerabilities: cold
Condition Immunities: blinded, deafened, exhaustion, poisoned
Senses: blindsight 60 ft. (blind beyond this radius, passive Perception 10
Challenge: 5 (1,800 XP)
Fire Feeding. Whenever the brown mound is subjected to fire damage, it takes no damage and gains a number of temporary hit points equal to the fire damage dealt.
Multiattack. The brown mound makes two slam attacks. If both attacks hit a Medium or smaller target, the target is grappled (escape DC 14), and the brown mound uses its Engulf on it.
Slam. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8+4) bludgeoning damage and 4 (1d8) cold damage.
Engulf. The brown mound engulfs a Medium or smaller creature grappled by it. The engulfed target is blinded, restrained, and unable to breathe, and it must succeed on a DC 14 Constitution saving throw at the start of each of the mound’s turns or take 8 (1d8+4) bludgeoning damage and 4 (1d8) cold damage. If the mound moves, the engulfed target moves with it. The mound can have only one creature engulfed at a time.
Call it lazy, call it focusing on modules, call it an experiment (the Monster Manual monsters seem hard pressed to fit into the guidelines given in the DMG), but I think this year I will instead of developing monsters largely from scratch focus on re-skinning monsters in the Monster Manual. This is a shambling mound but with a brown mold’s immunities and vulnerabilities.
DMs who don’t roll damage will find it does slightly less damage. It might seem a lot weaker due to having a vulnerability, but fire is a pretty strong immunity/healing source and the temporary hit points are a bit of an upgrade.