Folding Trap

Folding traps were invented by a master kobold trapmaker to aid in timely retreats. These devices are usually constructed by kobolds to provide quick installation of traps, as well as to easily carry along useful traps when they are retreating from their lair. (Knowledge (arcana) DC 15 or Knowledge (history) DC 25)
A folding trap is a small wooden ball the size of a large apple, every square inch of which has been etched with symmetrical Draconic runes. These carvings contain a hidden code that reveals the folding trap's command words. (Decipher Script DC 20) As a standard action, speaking the word "expand" in Draconic (turalisjth) causes the wooden ball to unfold into a trap that attaches itself to the available supporting framework (floor, ground, trees, walls). Speaking the word "shrink" in Draconic (kosjth), another standard action, while within 30 feet of the trap causes it to fold into a wooden ball once again. Several varieties of folding trap exist. The known variations on this item include the scything blade folding trap (CR 1), the wall blade folding trap (CR 1), the tripping chain folding trap (CR 2), the ceiling pendulum folding trap (CR 3), and the wall scythe folding trap (CR 4). Once activated, a folding trap is indistinguishable from a normal trap of its kind except for the trap's magical aura (see below).
Faint transmutation; CL 5th. Craft Wondrous Item, create trap, shrink item, creator must have 5 ranks of Craft (trapmaking); 1,700 gp, 136 XP, 4 days (scything blade); 2,500 gp, 200 XP, 5 days (wall blade); 3,800 gp, 304 XP, 8 days (tripping chain); 14,100 gp, 1,128 XP, 29 days (ceiling pendulum); 17,200 gp, 1,376 XP, 35 days (wall scythe).
Variants: Other varieties of folding trap might also exist, but they all must involve the use of mechanical traps that have an automatic reset (no arrow traps), don't represent a significant change to the physical environment (no pits or flooding chambers), and don't incorporate poison, magic, or living organisms (no toxic blades or brown mold). Weight: 1 lb. Price: 3,400 gp (scything blade); 5,000 gp (wall blade); 7,600 gp (tripping chain); 28,200 gp (ceiling pendulum); 34,400 gp (wall scythe).
Source: Races of the Dragon