an out of phase spider

[-Catherin-]

In Dragon Necropolis there are these invisible trap NPCs called "an out of phase spider"

If you walk over one of these traps you are supposed to get the text:

"an out of phase spider phases in!"

and then a normal phase spider spawns on top of you and attacks you. I have tracked a couple of these traps and walked all over them, but they don't trigger this text or spawn.