4th and Forever: Muck City

S02E12 Invasion

The Sliders arrive amidst a bizarre invasion, prompting Quinn to use the timer to disable one of the alien ships. Just as they make a narrow escape, they discover that their new adversaries possess the ability to slide at will, leading to their capture in the subsequent world. Once imprisoned, the Sliders realize that their captors are the Kromaggs, a formidable race determined to dominate every parallel universe they encounter.