17 Secret Video Game Bosses You Need To Beat Before You Die
15. Star Fox SNES - Slot Machine

How you get there: The route you have to take to access the secret stage where the Slot Machine resides is so obscure, it's a wonder anyone managed to find it. To reach the surreal galaxy where it calls home, you'll need access to the Level 3 Asteroid Belt stage. Upon entering, you'll need to continuously spam lasers at one of the giant asteroid on your right to destroy it, at which point an enormous Phoenix will emerge and start flapping about. Fly straight into it and you'll be taken to the Out Of This Dimension level.
Why you need to beat them: Uh, hello? It's a bloody giant Slot Machine. In space. This isn't a secret boss that you need to beat for the challenge, rather, it's something you need to experience just for how bizarre it is. Apart from the fact that the space around you is constantly warping and making you feel like you're on a really, really bad acid trip, your only method of beating the Slot Machine is shooting its lever and rolling three 7's in a row.
The reward? The psychedelic space distortion stops and you're forever stuck in an infinitely looping level. Worth it.