An awesome pegasus pony from My Little Pony: Friendship is Magic. Her coat is a pale cyan, her eyes are strong rose, her mane and tail are rainbow striped and her Cutie mark is a cloud with a rainbow-colored lightning bolt.
Related to "lasers" and "shoop da whoops", a "Royal Rainbow" is what happens when a taco is forced into the mouth of the person charging their laser. The caster instead releases a Royal rainbow, and possibly the swallowing of one's laser, and can end in the shooper asploding.
A situation "goes rainbowcake" when a perfectly innocent, frivolous conversation suddenly explodes into discord and strife; particularly when it becomes a political argument that never seems to end. While applicable in real life, rainbowcaking most commonly occurs in internet threads. The correct response when someone begins to rainbowcake you is to say "until it's frozen!" It spawns from the great rainbowcake apocalypse of 2014, which can be seen on The Concourse by googling "rainbowcake apocalypse."
The discussion about the relative cuteness of puppies versus kittens went all rainbowcake when Harriet called Abagail's viewpoints on the fluffiness of her tail taoist communist propoganda perpetrated by the lamestream media.
The highest level of excitement; it is often expressed with words or phrases like “full on” and “all the way.” Shouts of exclamation may accompany, creating laughter that is indecipherable from sobbing.
“TRIPLE rainbow excitement” is extremely rare and could cause you to spontaneously combust.
When I kissed Shannon goodnight for the first time I ran home jumping and yelling. That was some full-on double rainbow excitement, man!