It's simply a water cooler, an enemy encounter from DELTARUNE Chapter 3. It is only capable of attacking and saying various misspellings of the word bubble, but according to a random NPC in the same chapter, it is a sentient creature. More specifically, a transformed version of a Mizzle, an enemy from a later Chapter in the same game.
The water coolers are a common joke within the fandom for having unreasonably hard-to-dodge attacks.