Requires

Myrel, Shield of Argive must be on the battlefield. Lithoform Engine must be on the battlefield. Dross Scorpion must be on the battlefield. Krark-Clan Ironworks must be on the battlefield. Mana needed:

Steps

1. Declare Myrel as an attacker, triggering its ability.
2. Holding priority, activate Lithoform Engine's first ability by paying and tapping it, copying Myrel's ability.
3. Resolve the copy of Myrel's ability, creating at least two 1/1 Soldier artifact creature tokens.
4. Activate Krark-Clan Ironworks by sacrificing a Soldier, adding .
5. When the Soldier dies, Dross Scorpion triggers, untapping Lithoform Engine.
6. Repeat from step 2.

Results