I like the plasma sentinel's plasma cloud "does damage over time get out before it kills you" effect, but it's only used in that one mod. So I was thinking of two traps that utilize it to force movement and provide area denial.
This trap can be placed on any surface. When triggered, it extends a beam x blocks long, and follows after the raider at 70% the raider's speed. It does this continually as long as the raider is in range. This trap triggers indefinitely.
Notes: The intent is the beam chases the raider around as long as they're in range, but even if it touches it's not instant death. The range would be shorter than the Sentry Beam--probably 2-3 sblocks.
This trap connects two surfaces in a 4 block long, 1 wide line. When the raider steps between the two surfaces, the trap triggers, creating the plasma cloud-zone within the area. It lasts for x seconds before deactivating, and can activate indefinitely. To destroy it, shoot one of the two surfaces.
Notes: One of the benefits of this over say an incinerator is that the incinerator needs to be on a wall (or on a ceiling and shoot down, etc). The power stream could be placed on two floor tiles or a floor and a ceiling tile, and still effect a straight line. If it were changed so that the line could be anywhere within those 4 squares, some interesting angles could be created. It would be quite useful in narrow hallways of sideways ramps, which most traps can't fit in.