Zol

Zols are large slimes. In some games, they split into two smaller slimes called Gels when defeated.

The Legend of Zelda
In The Legend of Zelda, Zols move slowly around dungeon rooms. Attacking them causes them to split into two Gels. They usually appear in a matching palette to the dungeon walls, but in some dungeons it is black instead to blend in with dark rooms.

The Legend of Zelda: A Link to the Past
In The Legend of Zelda: A Link to the Past, Zols again appear in different colors depending on location, but no longer split into Gels. Instead of automatically being present in the dungeon rooms, they tend to sprout up from the floor in a black shadowy form following places Link walks, thus appearing to come from his shadow. They first appear in the Swamp Palace, where they are red, and appear in the same color in Thieves' Town. In the Ice Palace, they are light green. In Misery Mire, they are yellow. In this dungeon, an endless amount also drop from the ceiling in the room directly underneath Vitreous's room, suggesting its slime is forming them there. Finally, turqoise ones appear in Turtle Rock.

The Legend of Zelda: Link's Awakening
Now simply identified as "Gels" in English, both types from the previous games appear in The Legend of Zelda: Link's Awakening, albeit both hopping after Link. Their pear shape is replaced with more of an oval shape. Sometimes, the A Link to the Past-style ones additionally are found in trap chests. Ones that grow from the ground are always A Link to the Past-style, and they no longer follow Link's path in doing so. Additionally, strong weapons can defeat The Legend of Zelda-style Zols in one hit. In Link's Awakening DX, the The Legend of Zelda-style ones are red and the A Link to the Past-style ones are green. Slime Eye is a giant Zol boss who drops several A Link to the Past-style ones immediately before his fight.

The Legend of Zelda: Oracle of Seasons/Ages
In both The Legend of Zelda: Oracle of Seasons and The Legend of Zelda: Oracle of Ages, Zols of both types appear as they do in Link's Awakening DX, and are still a fairly common enemy.

The Legend of Zelda: Four Swords
In The Legend of Zelda: Four Swords, Zols appear in red and have a squat pear shape. They once again split into two Gels when hit. A boss called Dera Zol also appears. The design for Zols in this game can be found in the data for The Legend of Zelda: The Minish Cap, but it goes unused.

The Legend of Zelda: Four Swords Adventures
In The Legend of Zelda: Four Swords Adventures, Zols appear in blue and green, with the blue ones appearing from under lifted rocks and green ones growing from the ground and able to sink back under. Neither split into Gels. Blue ones also replace enemies who are caught within the Quake Medallion's shockwave. Blue ones first appear at Lake Hylia, while green ones first appear at the Field.

The Legend of Zelda: Phantom Hourglass
In The Legend of Zelda: Phantom Hourglass, Zols are green and look identical to Gels other than size. They are first encountered as part of a miniboss encounter in the Temple of Fire. Later, in the Temple of Courage, an even larger type that splits into two normal Zols is seen.

Link: The Faces of Evil
In Link: The Faces of Evil, Zols are a squat, purple enemy with angry eyes. They move slowly from side to side, and if Link touches a Zol, he takes damage. Link can defeat them with his sword. Bots act similar to Zols but are even smaller.

Zelda's Adventure
In Zelda's Adventures, Zols are red and appear in the Shrine of Water. They have a fairly large amount of health and do not split upon defeat.

Cadence of Hyrule: Crypt of the NecroDancer featuring The Legend of Zelda
In Cadence of Hyrule: Crypt of the NecroDancer featuring The Legend of Zelda, Zols of various colors appear as somewhat common enemies. They move a space on every other beat. When defeated, they split into two Gels.