Hunter Seeker Missile

From The StarCraft 2 Wiki

The Hunter Seeker Missile is an ability of the Terran Raven. It fires a slow moving explosive device at a selected unit that is capable of doing massive damage. The hunter seeker only lasts for a certain number of seconds at the end of which it diffuse and deals no damage. Thus, it can be dodged if the targeted unit runs away from it for longer then the duration of the missile itself. It cannot target structures, but can damage buildings by inflicting splash damage to units next to a building.