It is a skin of a humanoid being similar to a blaze, with a hide similar to an armor made of netherrack bricks

This being is a blaze which was deformed with the passage of time, its rods were combined in arms and legs and because of the immense heat that this produced, the netherrack was melted around it and bricks began to be created which they were joining him in his hide which he became over time in a strong armor
It is immune to water thanks to its armor, but cannot fly as before due to the weight that this armor produces