Its appearance is similar to that of an Octorok, except it is significantly bloated. Filled with air, the Octoballoon floats above the ground, but the air flowing in becomes too much as it will cause the Octoballoon to burst into eight smaller creatures that resemble miniature Octoroks. These mini-enemies will bounce around for a few seconds and then they will disappear.
Link is able to hit the Octoballoon before it blows up, but doing so is rather pointless, as it will blow itself up momentarily. Furthermore, Link can defeat the mini-octoroks left behind, but since they disappear in just a matter of seconds, there isn't much purpose in doing so. These mini-octoroks will do a 1/2 heart of damage if they come into contact with Link.
Palace of the Four Sword
In the Game Boy Advance remake of A Link to the Past a second Octoballoon can be found within the Palace of the Four Sword. This variation has an orange color, but serves a nearly identical function as the standard red Octoballoon . It won't leave quite as many smaller mini-octoroks when defeated. This Octoballoon is surrounded by more dangerous Orange Octoroks.
Octoballoon Sprite and Shadow from A Link to the Past.