Survival of the Fittest turns every creature card in hand into access to another creature in the library. Pay one green mana and discard a creature, then search for the creature the current situation needs. In a deck with a varied creature toolbox, that can mean removal, protection, card draw, or the next combo piece.
The discard is often useful setup rather than a pure loss. Reanimation decks can place an expensive threat in the graveyard while finding a creature that helps return it. Squee, Goblin Nabob can supply recurring discard material over successive turns, while creatures with graveyard abilities provide other ways to make the discarded card matter.
You can activate repeatedly if you have mana and creatures to discard. That lets you build a graveyard package or move through several searches, but the cards go to hand rather than directly onto the battlefield. You still need a deployment plan and enough mana for the resulting plays. The searched creature is revealed, giving opponents information about what may happen next. Survival rewards a high creature count and meaningful choices at different costs. A deck with only a few creatures may struggle to pay the activation cost consistently, while a toolbox filled with overly narrow targets can draw awkward hands. Keep the core deck functional without the enchantment, then use Survival to convert redundant creatures into the specific utility or threat that makes the next turn stronger.
