Slugterra - Season 1 Episode 13
Dawn of the Slug

A fun trip to the mall cavern turns un-deadly when the place is over run by the zombie-like victims of the Zombus slug. With Pronto zombified (not entirely a bad thing, the others kind of like this new, quieter, more monosyllabic Pronto), the rest of the Shane Gang must find the mysterious Mr. Saturday who controls the Zombus slugs -- and find a way to stop him.