Gamer is Wario's home stage in Super Smash Bros for Wii U. The fact that a morbidly obese grown man's home stage is a young kid's bedroom is the least disturbing thing about this place. While many stages are home to fearsome foes like Ridley and Metal Face, none are nearly as horrifying as 9-Volt's mother.
Gamer is based on the minigame of the same name from Game and Wario, an underrated Wii U game that was hated because it “wasn’t the game the Wii U needed” or some . Regardless, in the original minigame, 9-Volt had to beat his lil shota while his mother attempted to catch him in the act, and scold him for it. While she had a reason to stalk 9-Volt's room in Game and Wario, I don't know what her beef with the Smash Bros is. 9-Volt isn't even here, but his mother stalks over the fighters, and brutally mauls them if she sees them. She can come in through the door, look out of the window, come out of the TV or even the Gamepad. Wherever you go, you are not safe from 5-Volt. You can't run. You can't hide. Abandon hope, all ye who enter here. Unless you've played Metal Gear and know how to take cover, in which case you'll be alright.
Also, this stage is cel-shaded. So that's pretty cool.