Ice Shot (アイスショット Aisu Shotto) is the Ice Climbers's neutral special move move. The controlled Ice Climber, summons a small stalagmite of ice and hits it with a hammer so that it slides off along the ground, damaging whatever it hits. This move is mimicked by the CPU Ice Climber if it is with the human-controlled one, so two shots at a time can be shot along the floor. Unfortunately, it shrinks in size as it slides, making long range Ice Shots undesirable.
Although this attack only does around 2% damage for each chunk of ice, it can be very useful in attacking and defending if used correctly. With both Climbers, it fires two blocks. If used in mid-air, the Ice Shots fall fast until they hit the ground, and they travel very fast down slopes. If one gets reflected, the other can cancel it out. In Super Smash Bros. Brawl, if the CPU Climber is present, using Blizzard or Squall Hammer then immediately using Ice Shot may result in both Climbers facing different directions, shooting an Ice Shot left and right simultaneously. If used immediately after a jump, Ice Shot will send the Ice Climbers up a small distance up, like Mario's Cape.
It is possible for a high-damage opponent to be frozen by Ice Shot, but the chances are slim, and the effect is short lived.
Using Ice Shot at very close range can catch enemies with both the ice blocks and the hammers.
In Brawl, shielding will send the Ice Shot back at the Climbers, but not do any damage to them. It can also lock.
In Super Smash Bros. Melee, the projectile was able to absorbed by Ness's PSI Magnet to replenish his energy, but in Brawl it works as a solid item (meaning it has no energy properties and thus can not be absorbed by the magnet) and breaks through it (and Lucas's). Also in Melee, the hammers laid physical damage to those to close to the Ice Climbers while executing the attack (upward knockback). This is not in Brawl, either.
This move seems to be unique to Melee and Brawl. It is likely based on the enemies named Topi in Ice Climber. They could push a similar piece of ice, to block gaps. Of course, these pieces of ice where harmful to the Ice Climbers, who would die when in contact with it.
 Description from the Melee instruction booklet
Release sliding blocks of ice that follow terrain, but bounce off walls.
 Description from the Brawl instruction booklet
Hit chunks of ice that slide along the ground and bounce off walls.