Before it was made uninhabitable. (Credit to Sarge)

Linkit is a planet which is home to the Agrippa and Froog, along with many other species. It had rainforests, mountains, waterfalls etc, before Blackout's fleet attacked and devastated it. Most of the surface is now barren, and not much lives there anymore.

Somehow, Mondas didn't notice, and he also tried to attack it.