Cain Velasquez ain't really gunnin' for a WWE career -- so says his BFF, Daniel Cormier ... who tells us Cain's Brock Lesnar call-out at "Elimination Chamber" was just for fun.
Velasquez, who beat Brock for the UFC heavyweight championship back in 2010, hit up his first WWE event with Cormier last weekend ... and teased a fight with the Beast inside the squared circle.
"I could feel at home here! Brock Lesnar, I wouldn't mind taking another belt from you," Cain said on social media.
But Daniel tells TMZ Sports Cain was messin' around -- 'cause that's the kinda guy he is when he's not smashing his opponents' faces in.
That said, Cormier says Cain is dead set on making his UFC comeback this summer -- and wants to fight on the same card he's headlining vs. Stipe Miocic (UFC 226).
As for his opponent ... DC says that's TBD -- but we all know the door's open for Brock to return.