Unseen

When you Fail a Covert Skill Test in Freeplay, all creatures in True Shooting Distance(16u) gain a stack of Alert. If the creature was already at 2 stacks of Alert, you instead lose 1 Stack of Unseen. If you reach 0 stacks of Unseen, an Encounter begins.

Unseen is a Stealth Condition that applies to Freeplay.