Octorok

The Octorok is a conventional, octopus-like enemy that has appeared in every Zelda game to date except Twilight Princess, and has changed quite dramatically over the course of the series in terms of physicality and coloration.

Characteristics
The famous Octorok is an octopus-like creature that is best known for its method of attack; it shoots circular projectiles from it's cylindrical snout in short intervals, attempting to hit Link from afar. The rock shooting capabilities of the Octorok can occur at random intervals as in The Legend of Zelda, in the cardinal directions, as in A Link to the Past, or simply in Link's direction, like in Majora's Mask.

This foe is also known for it's top-heavy appearance and large eyes, seen vividly in the console titles; it adopted more of a spider-like appearance in titles such as A Link to the Past, Four Swords, and the Oracle games, and by comparison looks a bit more squid-like in The Wind Waker, Phantom Hourglass, and Spirit Tracks. The Octorok has adapted to life both within the water and on land, the former providing a protective barrier of water to hide beneath between projectile shots, and can be encountered even underwater, as seen in Spirit Tracks. Debuting in the original Legend of Zelda, the Octorok has changed little in terms of behavior across the series, varying the most in the fields of adaptivity and coloration.

Standard Octoroks, primarily in the 2D titles, are smaller than Link, receiving a significant size increase into the console games, to reach their largest physical size in The Wind Waker, Phantom Hourglass, and Spirit Tracks, rivaling the size of the King of Red Lions, S.S. Linebeck, and Spirit Train, respectively. Regardless of size, Octoroks are seldom seen isolated. For example, few instances in Four Swords Adventures showcase Octorok population densities in upwards of fourty creatures per screen. In addition, many Octoroks may populate an area but may not be in close proximity - the Zora's River region in Ocarina of Time is a good example of the distance between these creatures within a single region.

Only in Ocarina of Time and The Wind Waker does the Octorok appear as a mini-boss, the former waging against Link in a spiked circular arena deep within Lord Jabu Jabu, the latter appearing several times across the Great Sea with different numbers of eyes, safeguarding treasures from Rupees to Pieces of Heart. One of the Big Octos, as they are called in both titles, in The Wind Waker holds the very Great Fairy hostage that will reward Link an extension to his magic meter if rescued.

Another, exotic form of Octorok found in Phantom Hourglass is the Octomine, an explosive species that can only be found underwater. They are found in two forms: its sleeping form where they lie completely still and a wide awake form which propels itself underwater either up and down, or left and right.

Variation
While the grand majority of Octoroks differ in color, there are few species that inhibit unique traits. The Adventure of Link introduces the only jumping Octorok to the series, while Link's Awakening provides the Zelda saga with its only Winged Octorok, one that can evade sword slashes, but not an attack using the Roc's Feather. Other than that, however, Octoroks differ only in their coloration and physical appearance between games.

Red and Blue
Since the Octorok debuted in The Legend of Zelda, the apparent strength of the foe has been polarized through differences in color. Speaking of, the two mainstream varieties that exist in The Legend of Zelda, Four Swords Adventures, and the Oracle titles are of the red and blue variety, the latter being the stronger and the only one of the two to spit rocks.

Only the red and the red Winged variety appear in Link's Awakening, the former of which is the solitary staple in the previous two titles, The Adventure of Link and A Link to the Past.

Purple
The standard Octoroks seen in Ocarina of Time and Majora's Mask are purple, a trend carried into Phantom Hourglass and Spirit Tracks. In The Wind Waker, a pink and purple variety exist, the former shoots Bombs instead of rocks and appears frequently across the expanse of the Great Sea, while the latter remains a traditional rock-shooter appearing only in freshwater locales such as the Forest Haven. In Four Swords Adventures, a purple variety exists as well, however, it hesitates for a beat before shooting a volley of four rocks at Link in a row.

Gold
The Minish Cap, like The Legend of Zelda, incorporates a red and stronger blue version, but adds a Gold version which only appears as a product of a specific Kinstone Fusion. This Gold variety can also be encountered in Oracle of Seasons, and in both games, this iteration of Octorok requires many more hits than the average version to take down.

Winged Octorok
The Winged Octorok is an enemy unique to Link's Awakening, and appears to be an evolved form of the Octorok. These enemies will take flight if Link try to slash at them, Link must use the Roc's Feather to jump high and slash his sword in their direction. They also seem oblivious to charged spin attacks, so either holding the sword and walking into them, or simply unleashing a spin attack as the Winged Octorok will be unable to fly away in time.

Land/Water
In the ds games both land and water octoroks appear.

Weaknesses
The Octorok, regardless of terrain, can be defeated by any conventional weapon, such as the sword, bow and arrow, bombs, boomerang (only stuns in Ocarina of Time and Majora's Mask) and the like. In the same vein as the Dead Man's Volley, Link can also in some titles, use his shield, and in some cases, the sword, to reflect the projectile that the Octorok shoots back at it's face, vanquishing it. While this technique usually does not work on land-dwelling Octoroks, the water-borner variety are more than vulnerable to this technique.

Super Smash Bros. Series
Octoroks appear as enemies in the second level of Adventure mode in Super Smash Bros. Melee. They can, but rarely, be found in other modes in boxes. Octoroks do not appear in Super Smash Bros. Brawl.

The Crystal Trap
In The Crystal Trap, Octoroks appear after Princess Zelda frees Link from the Crystal. If the heroes choose to leave the Midoro Palace, they will struggle since Link feels too weak to walk. They eventually reach a forest and decide to rest, but suddenly Octoroks ambush them, and although Zelda tells Link that they should run away, the young hero feels too tired and thus must stay and fight. Choosing to stay and fight results in Zelda and Link taking cover from the Octoroks' attacks, with the young hero giving the princess some advice to defeat the Octoroks. By the use of her bow, Zelda defeats the monsters, but is exhausted from the battle. They then witness a Pink Fairy glowing out from the corpse of one of the dead Octoroks. The fairy thanks the heroes for freeing her from the monsters and rewards them by showing them where to find the weapon that will defeat Ganon: the Spear.

If the heroes choose to run away, Zelda will put her arm around Link's shoulders and begin to run. Trying to pull Link with all her might, she fails since she cannot outrun the Octoroks' attacks while carrying Link. A rock strikes Zelda's leg, causing the heroes to collapse and giving the foes a chance to surround them. The page ends with a Game Over as Zelda realizes she cannot hope to defeat all of the Octoroks by herself.

The Shadow Prince
The Shadow Prince briefly mentions the Octoroks when Charles of Moria is bragging of his accomplishments as a knight. He comments about the time that he defeat twenty Octoroks with just one swing of his ax, although Link is unimpressed by this feat, saying that "Octoroks are easy prey."

Trivia

 * An early screenshot of Ocarina of Time revealed several Octoroks walking on land like their 2D equivalents.
 * In Majora's Mask, shooting an ice arrow at an Octorok freezes them into a solid platform. This is an essential skill to learn in order to complete the Great Bay Temple as well as to reach the upper valley of Ikana Canyon.
 * Interestingly, in the Oracle games, wearing the Octo Ring will turn Link himself into a green Octorok, however, he will not be able to attack.
 * Phantom Hourglass is the only Zelda title to date that showcases both water-borne and land-dwelling Octoroks.