As of 5/8/21 it is now the location of the MEME boss's spawn. Items are so far not confirmed and will be found as more and more people find new items.
The area contains several rainbow crystals that can be broken with the special Crystal Breaker item that spawns in the left side of the area. the MEME boss spawns here also.
When broken, the crystals can give several rare items.
The items that can be earned are: (more needs to be found)
Nothing. Cash. Rainbow Cosmic Star. Rainbow Gaster Blaster