Darrell and Shannon are the characters from OK K.O.! Let's Be Heroes.
Darrell is the red male robot with one eye and shoots laser while Shannon is the orange female robot with deadly weapons as sawdust and shapeshifts.
They only appears as main villains in the post-Thanksgiving-Black Friday-Christmas-themed episode where they ruined the Super Black Friday. So, K.O. wants to stop them, but Principal Claus slams them to the ground.