Anvil

Anvil is a block. Unlike in vanilla Minecraft, it cannot be damaged by using it too much, but still can be damaged by falling.

Anvil Uses
Anvil uses are a vanilla minecraft mechanic that used to be in SkyBlock anvils, however it was removed in the enchanting update. The more anvil uses an item had, the more expensive it was to add another enchantment. Glitches were found and abused to remove anvil uses and reduce the cost of enchanting tools.

Combining Enchanted Books
The Anvil is often used to combine low-level Enchanted Books to increase their level. It takes two of the same level to increase, so it is not possible to get a level V book from 5 level I books. Instead, it would take a total of sixteen level I books to create a level V book. This does not work for all levels, however, as many high-level enchantments (usually level VI or higher) are obtained from Dungeons, Experiments, or the Dark Auction.

Combining Tools
Two items of the same type can be combined to add their enchantments, just like Vanilla Minecraft. However, unlike Vanilla Minecraft, it does not increase durability, because there is no durability in SkyBlock. For this reason, it is not recommended to combine tools of a high rarity because it is usually much cheaper to just add more enchantments than to get a second tool of the same type.

Upgrading existing Enchantments
An enchanted item can combined with an Enchanted Book of the same enchantment and level to upgrade that enchantment to the next level, just like Vanilla Minecraft. However, unlike Vanilla Minecraft, it costs no additional XP levels to do so, and as a result, gives no Enchanting experience. This is specially useful for more expensive enchantments, where the player cannot afford to outright acquire the highest level, and can instead opt for a more gradual progression.

Scam Prevention
Unlike Vanilla Minecraft, items cannot be renamed. This is to prevent people renaming cheap tools to more expensive tools that look similar and selling it on the Auction House (like renaming a wooden hoe, which is worth about 5 coins, to a Mathematical Hoe Blueprint, which can sell for over a million).

Bugs
There is currently a bug where if lagging and you spam shift click an item, you can sometimes obtain a barrier item the same as the one in the anvil.

Damaging the Anvil
In SkyBlock, players cannot damage an anvil by simply using it. The only known way of damaging an anvil in SkyBlock is by dropping it from a height larger than 1 block. The chance of the anvil getting damaged is 5% per block fallen. Of the higher the player drops it, the more likely the player is to break it in the first stage. When an anvil gets damaged for the 1st time it will turn into a, the 2nd time it gets damaged it will turn into a , and break completely the 3rd time it gets damaged.