New Dark Elixir Troop: The Mole

Training cost: 250 Dark Elixir
Training time: 20 minutes
Housing space: 15
Damage per second: 75
Hit Points: 300
Movement speed: 15
Description: The Mole uses it's sharp claws to dig under walls and resurfaces to attack defenses. When it is underground, it is undetectable by defenses until it resurfaces. It will leave a trial of dirt when it is underground so the players can see where it is digging next. While it is underground it's somewhat slow, but it makes up for it with good attack and hit point stats. I have also thought of a defense to combat the Mole: the Jackhammer (suggest different names if you want). The description of the Jackhammer will be in my other thread.
Here is an idea from google images but I would like the troop a little less cartoony:
http://howtokillthings.com/wp-conten.../12/mole12.jpg

This idea has been suggested loads of times before, please use the search function next time.

As for the idea, it doesn't seem too bad, but would it be affected by spells while digging ?