Rock Pet

The Rock Pet is a Mining Mount that drops directly from. Unlike most pets, the Rock is obtained via mining milestones, similar to the Dolphin Pet. Upon reaching a milestone a new rock pet is acquired, any previous rock pets are not upgraded.

Obtaining
The Rock Pet is obtained by reaching ore milestones. The milestones are as follows:

Note: To obtain the pet, players must mine a certain amount of ores. Blocks such as Stone, Netherrack, and End Stone do not count towards the total. However, Mithril and Titanium count.

Players used to have to use the SkyBlock API to see their milestone progress, However, this has been changed in Skyblock Update 0.11.4, allowing you to check the milestone progress in-game.

Trivia

 * While you can mine ores to upgrade this pet, it is generally recommended, for efficiency's sake, to upgrade it through Kat. (This is also the case with the Dolphin pet).
 * Any ores mined can spawn the Rock Pet. This can be on a private island (if the ores were placed by a minion), in the Coal Mine, at the Gold Mine, in any layer of the Deep Caverns, in the Dwarven Mines, and even The Park (gold ore spawns in the Savanna Woodland caves, although mining for a pet here is not recommended because of the low quantity of ores).
 * Previously unconfirmed, the Rock Pet can still be obtained even with the Smelting Touch enchantment.
 * While riding the rock pet, the player takes no knockback. This can be useful for Slayer quests and the Defend Jerry's Workshop event.
 * When sneaking at the edge of a block the Rock Pet will fall down. Jumping after it and right-clicking it mid-air makes the player sit in the air not moving as the Rock Pet glitches away. (It just falls down slowly now when your on it instead of floating on the air)
 * The Rock Pet is the first pet to have more than one skin in a Fire Sale
 * There has been a bug involving using the Rock Pet and right clicking with an item with an item ability. This would cause the player to be bugged and be able to walk around, break blocks, and place blocks, all while still being on the rock pet on other player's screens. However, this appears to just be a visual bug, as other players still see the player on the rock pet. This bug was shown in a Dragonhanx youtube video.
 * Rideable pets cannot be mounted on in dungeons
 * It's not recommended to upgrade the rock through Kat because it's usually cheaper to buy it of the auction house.
 * Using Kat to upgrade a rock pet means that, when you reach a milestone, you end up with another Rock Pet, meaning you could potentially end up with 5 Rock Pets. The amount of effort and time required to obtain 5  Rock Pets are prohibitive, and it is not recommended.
 * There is currently a glitch where when you die while riding a Rock Pet, you are dismounted from the pet instead of being sent to the island spawn.