Zol

A Zol is a recurring gelatinous creature that appears in the Zelda series. Attacking one usually splits the Zol into two smaller jelly-like enemies called Gels. Gel made their first 3D appearance in Phantom Hourglass.

Characteristics
The Zol's primary habitat ranges from dungeons and caves in Legend of Zelda and A Link to the Past, to the overworld in Link's Awakening, Oracle of Ages, and Oracle of Seasons. While Zols do yield two Gels, respectively, when struck with a weapon, it is possible to defeat these creatures through the use of a more powerful weapon (such as the white Sword from The Legend of Zelda) as such so that the enemy bypasses the Gel stage altogether. As their most common incarnation facilitates the split into the Gel form upon attack, it could be said that these creatures carry twice the vitality and by extension, offensive power as their Gel counterparts.

Interestingly, the Zol of A Link to the Past and Four Swords Adventures are the only incarnations not to experience a Gel phase when attacked, however, it is also the version in the most abundance, as it appears in three different colors across the Hyrule overworld and show a difference in vitality: the standard red are the simplest, while green and yellow are the most difficult to defeat. Coloration of Zols is not limited to A Link to the Past though, as Link's Awakening also incorporates red and green Zols: the red Zol is the stronger of the two and can divide into Gel if struck with a weak weapon (a strong one will simply defeat it), while the green version is much less powerful and does not divide into Gel upon attack. Also, in Link's Awakening and the Oracle series, only green Zols can pop out of the ground in an ambush, attacking Link in a radically different way in comparison to the commonplace, bouncing strategy of other titles' incarnations. In A Link to the Past, both green and yellow Zols can pop out of the ground.

Gel
When attacked with a weak weapon, Zols have the ability to split into two Gels, which appear to be smaller variation of the Zol. Gels are circular, often green or red blobs that tend to bounce aimlessly around wherever they are found, whether it be within a labyrinth, as seen in The Legend of Zelda, or across the overworld, as seen in Link's Awakening. Sometimes, Gels can appear without the presence of Zols. Overall, these foes are renowned in the Zelda universe for their weak attacks and slow movement, both of which make an enemy such as this a small threat to any who happen to cross paths with it.

The Gels present in Link's Awakening, Oracle of Ages, Oracle of Seasons, and Phantom Hourglass are quite unique in that they do not cause damage, but can attach themselves to Link's body similar to the way Morths do in The Wind Waker, impeding Link's movement.

Weaknesses
As Zols and Gels are often commonplace enemies, they can be defeated with the most conventional of weaponry, including the Sword, Bomb, Boomerang, Arrows, and the like.

Trivia

 * Slime Eye, the boss of the Key Cavern in Link's Awakening, is called or "Big Zol" in the Japanese version.
 * The boss of Talus Cave in Four Swords is a large slug-like creature called Dera Zol.
 * The Zol may have been the precursor to the Chuchus, seen in more recent Zelda games. Phantom Hourglass marked the first occasion in which both enemies appeared in the same game, and they can sometimes even be seen alongside each other. Chuchus in Skyward Sword split into two when struck, just like Zols, and cling to Link to attack much like Gels.
 * Zolgels (also known as Gelzols) are enemies in that are very similar to both Zol and Gels. Given the game's status in the canon they may not be directly related in any fashion, although the name is a direct reference.