Outlast

Outlast is a keyworded activated ability that was introduced as the clan-specific mechanic for the Abzan Houses in Khans of Tarkir.

Description
Outlast grants a +1/+1 counter on the creature for a cost, but it may also trigger other abilities.

The mechanic made a small reappearance in Modern Horizons.

Rulings

 * The cost to activate a creature's outlast ability includes the tap symbol (undefined). A creature's outlast ability can't be activated unless that creature has been under your control continuously since the beginning of your turn.
 * Several creatures with outlast also grant an ability to creatures you control with +1/+1 counters on them, including themselves. These counters could come from an outlast ability, but any +1/+1 counter on the creature will count.