Rugs of smothering were magically animated rugs that were commonly employed as traps. They attacked by trapping and constraining their victims.
There was a large variety of shapes and appearances that a rug of smothering could be made into. They sometimes were built to resemble carpets of flying, but were otherwise indistinguishable from ordinary, non-magical rugs, except if inspected through magical detection.
The typical tactic adopted by a rug of smothering in combat was to rise and constrict a target creature standing on it or next to it. The trapped creature could not breath while imprisoned, and was slowly crushed by the rug unless freed. While a rug of smothering had a creature in its grasp, it had the ability to deflect part of any damage it received to its victim.
Like all constructs, rugs of smothering were susceptible to antimagic effects. They immediately fell unconscious while inside an antimagic field, and could be knocked out for up to a minute if targeted by a dispel magic spell.