Upon death, these will spawn a portal to Whimsydale, and in this instance Princess Lilian can spawn. They are somewhat rare, so expect to find a lot of goblins before you find a Rainbow Goblin. These can spawn in any place in adventure mode, except in rifts and in the vault. In order to find Whimsydale, you first need to kill a Rainbow Goblin. They have a 100 % drop chance, but the real problem is getting her to spawn.
To get the Cosmic Wings, you need to kill a unique mob in Whimsydale called Princess Lilian. The wings were added to the game in patch 2.4.1, and can be used by any character after they have been obtained, even by hardcore or seasonal characters. The Cosmic Wings is a newly added vanity item that can be obtained from Princess Lilian in Whimsydale.
