Currently there are only 6 bosses, but I'm planning to add more.

Bosses

Compsognathus

Drops: Compsognathus Claw and 2.500 experience points
Health: 100 hearts
Speed: A tiny bit slower than players sprinting
Attack: 7 hearts
Knockback: 0.6
Immune to: Fire, Arrows, Fall damage
Spawns: Any type of jungle biome
How to beat: Full enchanted netherite, shield, a few golden apples, and lots of space to run around
Note: Very dangerous!

Ender Cow

Drops: Ender Pearl and 1,500 experience points
Health: Very tanky, 175 hearts
Speed: Fast as a player walking
Attack: 3 hearts
Knockback: 0
Immune to: Fire, Arrows, Fall damage, Dragon's breath
Spawns: Any end biome, including main island
How to beat: continuously hit it until you get low, eat some food, and keep doing it.

Tropical Slime

Drops: Slime balls
Health: 50 hearts
Speed: Fast as a player walking
Attack: 4 hearts
Knockback: 4
Immune to: Fire, Arrows, Fall damage, Explosions
Spawns: Beach Biome
How to beat: continuously hit it until you get low, eat some food, and keep doing it.

Evil Nitwit

Drops: Emerald
Health: 90 hearts
Speed: A tiny bit slower than players sprinting
Attack: 7 hearts
Knockback: 0
Immune to: Nothing
Spawns: Plains
How to beat: Tower up

Villager King

Drops: Crown
Health: 90 hearts
Speed: A tiny bit slower than players sprinting
Attack: 4 hearts
Knockback: 0
Immune to: Nothing
Spawns: Plains
How to beat: Bow and Arrows

Items

Compsognathus Claw

Drops from: Compsognathus

Drop rate: 100

Crown

Drops from: Villager King

Drop rate: 100

Custom Bosses