This unit can only attack units with 1 or more captivity counters on them.
Put 1 captivity counter on a unit without Stealth in the Ground or Character arena That unit gets -10 speed until end of turn. Play only when no unit is attacking.
Keywords
Stealth
Stealth: An isolated, static ability that means, "This unit can't be attacked unless it's tapped or has damage counters on it." An untapped and undamaged unit with Stealth can still be affected by alternative types of damage. (Such as Overkill.) As long as the unit has any number of damage counters on it, it can't use Stealth.