The Homing Missile is a weapon that seeks out nearby targets. It's usually used by the Sophia vehicles.
Sophia 3rd in Blaster Master uses this weapon; when fired, a single missile will quickly track and automatically target the nearest enemy. Despite the speed and relative accuracy, it's possible for the missile to get confused by especially quick or evasive enemies and simply whirl around for a bit. The missile is unobstructed by walls or other objects.
Sophia J-7's Homing weapon sends out a pair of blue missiles that lock on to and seek out nearby targets. The weapon must be charged before each shot. When fully upgraded, it unleashes six missiles.
This is a weapon used by Alex inside of Chambers. The shots from this attack will seek nearby targets, but only to a degree. It has five levels of power. With each level, the weapon will fire one more missile. At level 5, though, it becomes a fully-automatic weapon that spews out a storm of homing bolts. Though it's Alex's weakest weapon, the ability to home in on targets makes it a valuable asset.