The Scorpion Striker is the name of a Battle Pack and its Magic Item holder, available with Hot Dog and Series 2 Zap. In Skylanders: Giants, it unlocks the Metal Hive and Cliff Dive Crag battle arenas.
When used as a magic item, the catapult launches spiked explosive bullets at enemies. If they land on the ground or on the ground, they are ready to explode as soon as enemies approach them.
