Teleport Ender Creepers are a black version of a creeper. They are essentially creepers who enter the end and, like skeletons entering the wither, become altered in appearance and ability- common myth being that they were mutated by the ender dragon. Despite glitching up your game heavily, they appear to be intentional.
Attacks and Behavior
Teleport Ender Creepers are like regular creepers, but when they explode, you get warped to the nether, and you will find another ender creeper. If it explodes, your game glitches up until you refresh and reloade it.
Where else can it be found?
Overworld, Nether Caves, Herobrine's Mansion