Imagine if there was a episode that involved SpongeBob, Patrick and these other characters (In this picture down below) used the Vortex machine (the same one from Doodle Dimension) to save the Universe from Lord Boxman (from ''OK K.O.! Let's Be Heroes'') and Master Frown (from ''Unikitty!'') to foiled the good guy's plans to save the multiverse before it's too late (and this would be a ''Nicktoons Unite!'' In some way.)
Let me know down below in the comments or give me more suggestions.