my idea of a horror mob

so i recently thought of a idea of a bear that evolved it grew to be 18ft tall and 21ft in length i think this would be a great addition as a spawn able horror boss that follows you around your world and stares and attacks this bear should be a black bear with glowing white eyes that can stand up on its back legs from time to time it should be able to break blocks in its pursuit of the player it should spawn after placing 8 obsidian blocks in the shape of a square on the ground and a diamond block on the right side of the blocks immediately after placing the diamond block a loud roar should sound and the player will have to run and then from that moment until it kills the player or the player kills it or removes the diamond from the structure it will hunt the player removing the diamond block wont be easy however as getting within 30 blocks of the diamond block it will spawn there and charge at the player launching them 15 blocks away as well as stomping them into the ground with its front paws it can also have a pickup attack where it picks the player up in its mouth and throws them 10 blocks into the air which can be countered with the new wind charge soon to be added to the game it will have 150 hit points and it should be able to block and dodge certain attacks