These are wall mounted lasers that fire a continuous beam that has the same effect as the flame sword. there should be two types of them, stationary, which are used to restrain a player within an area (Robot boxing ring?), and moving, which, as their name says, move around, they could be used as regular obstacles, but much more destructive.
Malfunctioning Robotic Dog Head
Both an easter egg and a lethal trap, the MRDH is, as the name says, A big Doborog head in a wall, they should occasionally bark lightning, which would paralyze robots and remove random voxels (Not from the head or right arm, please), slowly damaging them, and leaving them open for attack.
Imagine a regular day in the Danger Zone Arena, the human is waddling around because his leg got shot off by a camping MK3 Combat Archer (True story, BTW), and, the unsuspecting human doesn't realize the blinking dot on the floor, steps on it, and pop goes the flying robotic guts, the landmines would be completely invisible, except for a beeping noise, and a faint red glint on the floor, when stepped on, these explosive traps should be about 2x stronger than a Spidertron Grenade.
These would be an unique trap, there should be normal auto turrets, which are mounted around the level and are destructible, they should fire a long ranged and unblockable version of the Spidertron Grenade fragment, but, there should be a special one, during a story (And possibly some endless) level, the giant carrier that brings The Emperor in the Arena should reveal a BIG version of the megagun, and crosshairs would start chasing you around, if one of them catches you, after about half a second a giant energy blast would be shot in that location, decimating everything nearby.