The will to return can overpower the will to survive.

Dread Return

Return target creature card from your graveyard to the battlefield.
Flashback—Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Those who forget the horrors of the past are doomed to re-meet them.

Commander Masters

Return target creature card from your graveyard to the battlefield.
Flashback—
Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

The luckiest acolytes were those who didn't survive long enough to see the archfiend's return.

Return target creature card from your graveyard to the battlefield.
Flashback—
Sacrifice three creatures.

Dominaria Remastered

"Bolters, flamers, plasma—we hit the xenos with everything, and it just kept coming."
—Captain Uriel Ventris

Warhammer 40,000 Commander

"Flashback [cost]" means "You may cast this card from your graveyard by paying [cost] rather than paying its mana cost" and "If the flashback cost was paid, exile this card instead of putting it anywhere else any time it would leave the stack."

A spell cast using flashback will always be exiled afterward, whether it resolves, is countered, or leaves the stack in some other way.

If a card with flashback is put into your graveyard during your turn, you can cast it if it's legal to do so before any other player can take any actions.

To determine the total cost of a spell, start with the mana cost or alternative cost (such as a flashback cost) you're paying, add any cost increases, then apply any cost reductions. The mana value of the spell is determined only by its mana cost, no matter what the total cost to cast the spell was.

You can cast a spell using flashback even if it was somehow put into your graveyard without having been cast.

You must still follow any timing restrictions and permissions, including those based on the card's type. For instance, you can cast a sorcery using flashback only when you could normally cast a sorcery.

You choose the target for Dread Return before paying any of its costs, so it's not possible to cast it using flashback and bring back one of the creatures you sacrifice.