Breethen and Breethen Worms.

Small bloodworm-like sand worms about 1 to five blocks long, has 3 hearts as a Breeling, 5 hearts as a Prebree, and 20 health as an adult. Attack most mobs except The Wither and Ender Dragon by biting with teeth. Roar when the player or any mob is within 8 blocks. Commonly found in water and caves. Spawns in dark areas in the Overworld and Nether. Turns a villager into a Breethen. Deals 1 heart of damage as a Breeling, 2 as a Prebree, and 7 as an adult. Will touch mobs and players to inflict damage and convert villagers into Breethen. They are grey.

Breethen are 2 block tall hostile mobs that attack mobs and players like their worm counterpart. They are villagers that have been convertedby Breethen Worm bites. They have 24 hearts of health and deal 8 hearts of damage. They are grey and will infect any nearby villagers within 6 blocks of them and will attack players until they die. Villagers' eyes will turn yellow after 2 ingame days, then will find somewhere isolated as long as it's within the village, and become a Breethen. Breethen and Breethen worms will only attack mobs that are on the ground, but may attack them if they see a possible path leading to the mobs. They eat meat and will attack cows, pigs, sheep, chickens, rabbits, and will also attack zombies, zombie pigmen, hoglins, piglins, and zoglins.