Almost all cartoons have done a crossover. But here's one we never think of :
Oggy and the Cockroaches X SpongeBob SquarePants

They're the best shows, about to get even better! If YOU support this cause, please sign this petition. This change will impact me and my friends and all of you too. This will make our lives filled with laughter. Only YOU can make a difference. A drop leads to an ocean. Share this with your friends too. We are dead serious about this. .. 
SUPPORT US! BRING LAUGHTER TO THIS DEPRESSING WORLD!