Mothraya (モスラーヤ Mosurāya) is a giant robotic moth originally used for ice breaking, 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, Pharaoh Shot, 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. Pharaoh Shot, while it deals normal damage, can be used to deal additional damage if the player is willing to risk moving along the floor with the boss.

Damage data chart

Amount of damage in units that Mothraya receives from each Special Weapon in Mega Man 4.

Mega Man 4
Mega Buster Flash Stopper Rain Flush Drill Bomb Pharaoh Shot Ring Boomerang Dust Crusher Dive Missile Skull Barrier Wire Adaptor
1:3 0 0 2:2 1:3 4 2 0 0 1

*For Mega Buster and Pharaoh Shot, the first digit is when the weapon is fired normally and the second is when it is fully charged.


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