The Iceball (ビッグアイスダス,Biggu Aisudasu?, lit. "Big Icedus") is a sub-boss in Sonic the Hedgehog 3 that the player will encounter at the end of IceCap Zone Act 1. It takes six hits to be defeated.
Created by Dr. Robotnik, the Iceball is a floating frosty machine that floats around the arena with eight snow blocks guarding it. It has a gray main body and three magnetic ends on the body's sides and bottom. It also has what it looks like two eyes and a mouth.
After getting out the cavern of IceCap Zone and into the cold outside weather, the player encounters the Iceball, which flies down into the arena. It then summons eight ice blocks from the snowy ground which it uses as shield, and swoops down in a U shape across the screen once or twice. It will then launch the ice blocks into the air, where they will eventually fall down to the ground. Depending where the Iceball is standing, three ice blocks will usually fall to the left side and two others will fall to the right side. The player cannot destroy the ice blocks and will take damage when touching them. After this, the Iceball will repeat its attack pattern again.
During the fight, the Iceball will be too high to reach at first. The best chance to hit Iceball is after it throws its ice blocks above the screen, as it is at this point where it is closest to the ground. However, the player can also hit it normally by using the Lightning Shield as Sonic at the right time or by flying as Tails. After six hits, the Iceball will be destroyed and the background will become brighter than before.
In Sonic the Hedgehog 3 & Knuckles, Knuckle will go through his own pathway to the lower part of IceCap Zone Act 1 and face the Iceball in a huge cavern. The battle is the same, except that it may take longer due to Knuckles' low jump height, which inhibits him from hitting the Iceball as often as with Sonic and/or Tails.