What it does
Eternalize lets you pay a cost (and exile the card) from your graveyard to create a token copy of that creature—but the token is always a 4/4 black Zombie, regardless of the original's stats and color. It keeps the original's name, abilities, and other characteristics. You can only do this as a sorcery (your main phase, empty stack).
The most common mistake: people forget the token's power and toughness become 4/4 and its color becomes black—this matters for things like power-based effects, color-based removal, or "creatures with power 3 or less." Also note it's "exile this card," so it's a one-shot per card, unlike Embalm which works similarly but doesn't change to 4/4 (Embalm tokens copy original stats).
In Commander, Eternalize gives strong graveyard recursion that dodges most reanimation hate, and the 4/4 baseline can buff small creatures into beaters.











