Gameobject blocking player

Hello, I was working on the Throne of the Tides dungeon and ran across a problem - there should be tentacles blocking the way to some parts of the dungeon (just like doors usually do) and can be seen here: www.youtube.com/watch?feature=player_detailpage&v=xhPOea_iMJQ&t=65 I have already indetified them in DB entry 208302 and 208301 and spawned them into (probably) exact location. But I have no idea if it is possible to make them collide the player and don’t let him get through. So is there any way to accomplish this (i was thinking about some invisible wall)? Thanks for your help!

how about trying to activate the GO when someone enters the dungeon?