The Slime Trap?

Wouldn't it be interesting to have a sort of a trap that slows down troops up to 15%? It would probably need some balancing but I could definitely see this being in the game. So to get into a bit of detail... The slime trap would be most effective against fast troops such as the hog riders, valkries or goblins. But would be a pain against slow troops such as the golem or the giant. I see this new feature as being a sort of a bomb so that it affects everything in a 3 block radius just like the regular bomb.