This trap seeks out chaotic creatures (which likely does not include player characters, though they do love to make mayhem) that touch it, and curses them.
Detect: Per-based Thaumatology, or Perception + Magery for mages, at -6.
Circumvent: Automatic (don't touch the trigger).
Evade: Resist Will.
Effects: -2 to all ability and skill rolls until the curse is broken.