Courage the Cowardly Dog Season 2 Episode 5 - Human Habitrail / Mission to the Sun Human Habitrail:A gerbil doctor, pretending to sell vacuums, shrinks Muriel and Eustace, planning on using them for an experiment of his abstract products. Courage sets out to win his owners back. Mission to the Sun:The sun is about to go out, so Courage and his owners go to outer space to fix it. Meanwhile, a tiny space-dwelling creature named Mustafa al Bacterius goes inside Muriel's brain and starts making her go insane so that their mission ends up disastrous. He wants them to fail because he along with all the other aliens see all Earthlings abusing their planets, and that all aliens like the dark.