Ice Slasher

Ice Slasher (アイススラッシャー) is Ice Man's Special Weapon. It takes the form of an arrowhead-shaped blade of ice that can freeze enemies with a temperature of 200 degrees below zero.

Mega Man
Mega Man receives Ice Slasher after defeating Ice Man. Only one Ice Slasher can be present in the screen at a time, and it passes through most obstacles. This is Fire Man's weakness, and except for him and the first form of Wily Machine 1, all bosses are immune to it.

Ice Slasher doesn't cause any damage to enemies, but it can be used to temporarily stop them, allowing Mega Man to switch to another weapon and attack frozen enemies. It is specially useful to stop enemies like Flying Shell, Sniper Joe and Big Eye to safely pass by them. When the flame geysers that appear in Fire Man's stage and in the first stage of Dr. Wily's Robot Manufacturing Plant are frozen, they can be used as steps.

Mega Man: Powered Up
Ice Slasher now can cause harm to all bosses due to Ice Man being a playable character, and it can do a very small amount of damage to enemies. Ice Man can use frozen enemies as platforms to reach higher areas.

Mega Man: Dr. Wily's Revenge
Like its appearance in the first Mega Man game, Ice Slasher is obtained from Ice Man and is Fire Man's weakness. Flash Man is also weak to this weapon. Cut Man, Elec Man, Heat Man, Enker, and Wily Machine I are immune to it.

Mega Man: The Wily Wars
Like all weapons from the first three games, Mega Man can use Ice Slasher in the Wily Tower mode. This is one of the weaknesses of Mega Water S. The second form of the Wily Machine is immune to it.

Mega Man: The Power Battle
Ice Slasher is obtained by defeating Ice Man in the Mega Man 1~2 course. It is Heat Man's weakness.

Other appearances
Bad Box Art Mega Man can use the Ice Slasher as an attack in Street Fighter X Tekken.

Ice Slasher is one of Mega Man's custom Side B Special Moves in Super Smash Bros. for Nintendo 3DS / Wii U. Whilst it does less damage than the Crash Bomber or Danger Wrap, it can pierce through multiple opponents with one shot, and at higher damage percentages, freeze them.

Mega Man
Damage values for the original Mega Man.

Mega Man: Dr. Wily's Revenge
Damage values in Megaman: Dr. Wily Revenge.

Other media
Mega Man uses the Ice Slasher in the Mega Man animated series. However, it differs from its in-game depiction in the fact that it takes the form of a beam of shatteringly cold energy, being able to freeze almost anything within a few seconds of exposure.

At one point, when Ice Man himself used it in Episode 7, he froze Rush with it before kicking him, shattering him to pieces. He also used it to provide the icy armour for the "Ice Bots" he used later to attack Doctor Wily and Air Man after they landed in the city.

Curiously, it was not referred to by its actual name, but was referred to as the "Freeze Ray" by Ice Man when he calls for Air Man's help after Mega Man copies it from him.

Artwork
Ice Slasher