This Gruul Eldrazi combo deck's engine hinges on Blade of the Bloodchief, a one-mana Equipment, which Meltdown with X=1 or higher blows up outright alongside their cheap artifact answers like Vexing Bauble and Soul-Guide Lantern. Unholy Heat is excellent instant-speed interaction that can kill Basking Broodscale or Glaring Fleshraker before the combo loop starts, since both are low-toughness creatures. Mutagenic Growth and Violent Urge don't interact with their combo plan and are better spent as interaction, since this matchup is decided by whether we can remove Blade of the Bloodchief or Broodscale before they go off. We race while holding up cheap removal to disrupt their engine pieces on sight.