Mothraya

Mothraya (モスラーヤ) is a giant robotic moth, and is the boss of Cossack Stage 1 in Mega Man 4. The red flashing light is its weak point, and Ring Boomerang is the best weapon to use (though Drill Bomb and Dust Crusher are also good options). It can thrust its spike-tipped "proboscis" into the floor, causing a part of the floor to be destroyed.

Trivia

 * Mothraya's name is a nod to the fictional Japanese movie moth monster, Mothra.