Everyone loves traps, but why not introduce a new, strategic trap called the Hidden Wall Trap. It is just as it sounds, it allows for you to leave patches in your base that troops will want to go through, but when they come near, a hidden wall sprouts from the ground blocking their path.
Though unneeded, it could have a spring trap effect for its activation and remain a wall after the fact. It must also be able to be leveled up
