Rhaumbusun (5e Creature)

Small monstrosity, unaligned

Armor Class 10
Hit Points 5 (1d6 + 2)
Speed 20 ft.

Proficiency Bonus +2
Senses passive Perception 8
Languages —
Challenge 1/4 (50 XP)

Paralyzing Gaze. If a creature starts its turn within 30 feet of the rhaumbusun and the two of them can see each other, the rhaumbusun can force the creature to make a DC 12 Constitution saving throw if the rhaumbusun isn't incapacitated. On a failed save, the creature is paralyzed as its muscles magically freeze in place. It must repeat the saving throw at the end of each of its turns. On a success, the effect ends.
A creature that isn't surprised can avert its eyes to avoid the saving throw at the start of its turn. If it does so, it can't see the rhaumbusun until the start of its next turn, when it can avert its eyes again. If it looks at the rhaumbusun in the meantime, it must immediately make the save.
Celestials, constructs, elementals, fiends, oozes, plants, undead, and other rhaumbusuns automatically succeed on this feature's saving throw.

Timid. The rhaumbusun has disadvantage on saving throws against being frightened.

A coiling rhaumbusun, source.

The rhaumbusun is a distant herbivorous relative of the basilisk, primarily sustaining on fireweed, soft woods, and nuts. They are largely timid creatures; when one feels threatened, it will most often paralyze any offenders with a glance of its gem-like compound eye before scurrying into a rocky crevice, or attempt to bite the paralyzed offenders to death if left with no other option.
Rhaumbusuns typically nest in life-mated pairs in tight caves, especially those of the Central Steppes of Taan in Eastern Faerûn, the Pasocada Basin and the mountains surrounding the Valley of Nexal in Maztica, and the islands and deserts of Zakhara. These pairs lay a single egg each spring which hatches some 45 days later, and reaches adulthood 20 days after. A rhaumbusun that has lost its mate or spawn, even just from momentary separation by means that their clicks and hisses can not be heard, mourns deeply, often withering and becoming unable to properly focus its gaze.
Most rhaumbusuns fill their burrows with all manner of shiny baubles that they collect while foraging. A few have been known to loot coins, jewelry, and gemstones from corpses, though this seems to be rare. Many timid carnivores form a symbiotic relationship with rhaumbusun, feasting upon the creatures they paralyze in exchange for protecting the burrow while one is foraging or if it is attacked.
Rhaumbusun are often sought out for magical purposes. The ink extracted from a fully preserved eye greatly expedites the process of creating a scroll or potion of hold person, fetching a typical asking price of 200 gp. Meanwhile, much like a basilisk, a rhaumbusun hatchling can be taught to avert its gaze from its master and to direct its gaze at a target, potentially as a conscious anesthetic, making an egg worth at least 500 gp, and a captured breeding pair worth upwards of 2000 gp.