What it does
Blitz lets you cast a creature for an alternative cost, usually cheaper than its mana value. When it enters, it gains haste and "When this creature dies, draw a card." At the beginning of the next end step, you sacrifice it. So you get an aggressive one-turn attacker that replaces itself when it leaves.
The big nuance: the card draw triggers when the creature dies—but you sacrifice it at end step, which counts as dying, so you still draw. People also forget Blitz is an alternative cost, not a discount, so you can't combine it with most "reduce the cost" effects on top of other alternative costs. Also, the haste and sacrifice are baked in regardless of how you cast it normally versus blitz.
In Commander, Blitz shines for surprise burst damage, sacrifice-fodder synergies, and value flickering. Just remember if the creature survives combat, it's gone at end of turn unless you blink or flicker it before the sacrifice resolves.













