Look at the multiverse series if you wanna get a good description.

You bought some doritos and found non other then BILL CIPHER in the bag

Holy crap it's real engineer from tf2

Holy snickers! I am not forcing you too be gelatin this time:0 but now I'm forcing you to be leafy >:]. Anyways this is the scene where Leafies and firies relation increases. This scene is in episode 21 season 4 of the hit show BFDI. (Have fun pookies!!!)

Basically T.P.O.T. Episode one also uh i don't really feel like adding every single character. Also ypu can be anyone in the show i don't really care if it's a OC or not.

If you watched BFB 17 you probably know what this is about.