The Device Trap Set 'Hanisbroner's Surprise' [+25]
It must be loaded with a magic device (wand, staff, or rod), which will
fire its spell at the monster who triggers the trap.
A magical trap, armed with a wand. Unaccountably, its victims keep on
coming back for more...
It is well-hidden. It rearms itself. It can teleport monsters to you.
It fires missiles excessively fast. It cannot be harmed by acid,
cold, lightning or fire.
Level 20, Rarity 20, 4.0 lbs, 20000 Gold

(T.o.M.E. 2.3.5)