The Louds and Casagrandes vs. Invader Zim: Back to the Florpus

Back to the Florpus is a crossover event that involves three Nicktoon series: The Loud House, The Casagrandes and Invader Zim.

Summary
The Tallest, learning that another Earth in another universe has all sorts of good snacks, food and drinks, trick Zim into moving from one universe to another. When Zim relocates to the Earth of the Savino Universe, he settles in Royal Woods and prepares for the Tallests' arrival.

Hoping to get some samples' of Earth's snacks for the Tallest, he tricks some earth children: Lincoln Loud, Ronnie Anne, The Loud Siblings, The Casagrande Kids and all their friends by promising them to make their parents 'go away' for a while when they host a big party, provided they help him get some samples of certain snacks and drinks like Flipplies.

But when they learn that Zim is actually an Ailen and is bringing his leaders to Earth to invade, they must rely on the help of Dib, Gaz and Professor Membrane, who for some reason follow Zim's tracks to their universe to put a stop to Zim's plan.

However, just who is the real villain?: Zim or the Tallest?