Watch this short animation by Spookiz and subscribe to their channel if you like the cartoon.
The monsters are chatting in the classroom while the big blue guy is sleeping and snoring in the back. Skeleton teacher enters the room and offers sweets to whomever is able to solve the Rubik's Cube. The little monsters try their luck one by one. One of them can solve only one side, the little girl puts stickers on the sides, the Dracula-looking guy is just polishing it. The zombie girl is just turning it slowly when the blue monster wakes up and swallows the cube. Seconds later he spits it out in solved position and receives the well-deserved jelly.