Hidden wall, its like hidden trap. When step on it, it will throw troop away like usual. Extra new ability for this is that it make one block wall on this location, when troops are bounced away. Can be upgarded. Might have some weight ability. Level 1 wall trap bounces example light troops, like archers barbarians. 2 level +wizards, and 3 level +gigants. And final upgarde level, heroes, with out Golem. Or like so
Maxinum hidden walls 2