In Junkyard Tussle, right before entering the room to fight Noiman Cascade, if the player climbs up the wall, they will find a mysterious character who will ask if they want to fight in the battle arena. If the player agrees, they will enter a crowded fighting arena where they will fight Simondo Belmont, Psycho Mother, and the Warp Bomber.
The Warp Bomber appears to be a mixture of flesh and metal with a fiendish face in the center and steel plates on the side. It has the ability to launch bombs from its mouth that detonate after a set period displayed on a counter on the bombs, and also launches homing missiles.
It can also can escape into an inter-dimensional portal and emerge in another one in a different location, although this can go out of control and cause a fold in the time-space continuum leading to time traveling results.