Goofball isn't actually a Pari, in fact, it doesn't even belong in Genshin Impact! It's actually some sort of sapient Computer virus (most likely Trogan Horse) that was around during the 2000's. It originally infected sketchy copies of a now forgotten MMO. But after said MMO got deleted and forgotten, it somehow managed to infect other games until settling on Genshin (For now).
Some says that if you try to download Genshin off a Sketchy website, or even try to get free primogens via those "free [blank]" websites, there's a slight chance of Goofball getting access to your computer. You'll most likely see it while exploring Sumuru... before causing a lot of pop-ups to appear and the computer crashing, as well as your copy of the game getting deleted. Other than that... it's pretty chill! You could even try to befriend it.
It is based off on the "You are an Idiot"/ Offiz Trojan Horse, Sparkledogs and potentially early 2000's Creepypasta. It can shapeshift, and you can see the original form of it here (Chimera).