In diablo 3, there is this creature that keeps popping up, and i am not sure what it is. I thought it was a treasure goblin, but everyone keeps talking about canceling it's portal, or whatever. After it dies, giving me a lot of gold and stuff, it leaves a rainbow portal. i went through it, which led me to this creepy, girly world where unicorns, care bears, and flowers try to kill me. after clearing the map, i went back through it, and it took me back to the same place. it happened when i was going through these towers, disabling something. Is it a treasure goblin or not?
Yes, it is a Treasure Goblin. More specifically, it is a Rainbow Treasure Goblin. These fine creatures spawn entrances to Whimsydale (which is different to Whimsyshire, at least in name).
Yep, it's definitely a treasure goblin. You got lucky, though, and it opened a portal to Whimsyshire. It's a "secret" area (but not really so secret), where everything is brighter and more cheerful, and you fight things like horses, unicorns, flowers, and teddy bears. It's meant to be a dramatic departure from the rest of Diablo 3.