Mechanical guardsman, Uncommon 16b
Unliving. Runic. Skirmisher.
Attack: 8
Mode 1:
Wall: +24
Mode 2:
Tower: +16
As someone who plays Unliving in probably half of his games, let me be the first to say that this card would be amazingly overpowered. It's on par with cards that require several Unliving in hand and lack Runic, and the Unliving keyword means you're likely getting a refund of 9, 12, or 15 bricks.
In my opinion, it would be well balanced if Unliving were to be removed. I don't think that's the ideal solution, however. I'd instead scale back the wall/tower choices to no more than 16/12. Increasing the cost is another option. Probably doing both.
I'd love to add an Uncommon Skirmisher to my Unliving deck... Kind of wanting to see this happen.