Infiltrate: +1 Attack and Flying.
Flying - Flying units can only be blocked by other flying units, but can block ground units normally. They can also be directly attacked by Killer units and Relic Weapons.
Infiltrate - The special ability of a unit with Infiltrate occurs the first time that unit hits the enemy player. It doesn't work while the unit is on defense, such as when it is attacked by a Relic Weapon.