Often found near tallstriders, glowtongues are somewhat less mysterious if only because their habits are more normal to us.
Glowtongues look not unlike a rhinoceros or hippopotamus, though about half again taller than those creatures, and its back legs resemble that of a human. However, they possess no mouths; instead, spectral green tentacles dangle from their heads where their mouths would be. Posthumous inspection has revealed these are thin physical tendrils that glow brightly with a magical energy in life.
To feed, glowtongues capture their prey, then reach out with their tentacles and literally drain life from their prey into the glowtongue's body, which glows slightly during the feeding. They capture prey thanks to the immense, spiked claws on their front legs, which which they bash and strike their prey, pinning them to the ground. Glowtongues prefer to hold their prey down instead of pierce it, apparently understanding that an impaled creature loses its life essence quickly, but are smart enough to know when the latter is necessary.
Glowtongues live and move in small herds of a few dozen, capable of short bursts of speed of up to 40 miles an hour, but they are otherwise easy prey for humans. Their preference for more desolate habitats and the generally bland flavor of their meat have kept them mostly unmolested by humanoid hunters, though some remote tribes hunt them with fervor.
However, one curious aspect of glowtongue behavior brings them into occasional conflict with the sapient races: glowtongues exhibit a keen curiosity about magical artifacts. If a herd of glowtongues finds a loose magical artifact, its members will excitedly probe it, then drag it to a place of safety and visit it frequently, almost like devotees with an idol. They will viciously attack any other creatures who approach "their" artifact.
For stats, I'm going to go with the hezrou, a CR 8 brute that roughly matches what I'm looking for here. I'll swap out its damage resistances, immunities, and stench with a powerful life drain attack that only lasts until the target takes a long rest.
Looking at those changes, I'm actually pretty happy with that. Let's do this!
Homebrewery stat block:
Large beast, neutral
- Armor Class 16
- Hit Points 130 (13d10 + 59)
- Speed 30 ft.
STR DEX CON INT WIS CHA 19 (+4) 17 (+3) 20 (+5) 5 (-3) 12 (+1) 13 (+1)
- Saving Throws STR +7, CON +8, WIS +4
- Senses passive Perception 11
- Languages None
- Challenge 8 (3,900 XP)
Magic Resistance. The glowtongue has advantage on saving throws against spells and other magical effects.
Multiattack. The glowtongue makes two attacks, one with its life drain and one with its claws.
Life Drain. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit 15 (2d10 + 4) damage. The target's Hit Point maximum is also reduced by this amount until the target completes a long rest.
Claws. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit 11 (2d6 + 4) piercing damage.