Just thinking

How about a mole like creature? It would be protected underground. Be able to go under wall. Its favorite target being a mortar, or just defenses in general. It would have low health since its invulnerable underground. An OK hit point count, with a medium speed. Trained using dark elixer. I feel like this would be a cool new troops to have. Or you could make it like a goblin style troop that loves to tinker with defenses to make them malfunction for a short period of time. To make it not op maybe have it take up a lot of troop space