Is there a Wizard of Gauze in Gauntlet? I know there's one in the Dungeon campaign, and here's a video solution using zero mana:
http://youtu.be/YAYLTnAW_8E

If it's your first time on that level, you wouldn't have tribal-ista yet, so you would use mana and whatever defenses you do have.

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Tcarr9's Tiny Heroes video walkthroughs are available on YouTube: http://www.youtube.com/user/Lordkalvanmidnight