A powerhea, bang stick, or shark stick is a specialized firearm intended to be used underwater and fire in direct contact with the target. These are often used for spear fishing, or they may be used against sharks or alligators for sport, defense, or to kill nuisance animals. The term powerhead generally refers to just the firearm-like part of the device; when attached to a shaft to form a spear, they may be referred to as a bang stick or, if intended for defense against shark attacks, a shark stick. The spear in question may be handheld, or launchable from a spear gun.