One of Ironclad's trickiest cards, both to evaluate and to use correctly. In the simplest situation, you might play a Headbutt to put a strong card you'd like to play on top of your deck, and then play a Havoc+ for 0 in order to play that card for "free". Havoc is often much more complicated than that, though. A 0-cost (when upgraded) way to cause an exhaust trigger which draws cards with Dark Embrace can end up in situations very complex situations.
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