Here are some random ideas, hopefully not too many of them are repeats of previous suggestions:
Motion detectors
Security cameras/floodlights
Moving security beams
Retinal scanners (steal an enemy's body?)
Mines
Thwomps (spinoff)
Patrol bots (scouts)
Alternating on/off laser beams
Rising platform - (If you step on it, it races toward to ceiling, smushing you when you get stuck between it and the ceiling)
Electrocuting tiles
Motion detectors
Security cameras/floodlights
Moving security beams
Retinal scanners (steal an enemy's body?)
Mines
Thwomps (spinoff)
Patrol bots (scouts)
Alternating on/off laser beams
Rising platform - (If you step on it, it races toward to ceiling, smushing you when you get stuck between it and the ceiling)
Electrocuting tiles