Medusa

You know it and its true. We need better boss mobs that are not so huge and dont cause lag and things like that. Maybe a powerful stone turning war machine named Medusa can fit the roll.

Medusas powers
Medusa is a popular Greek myth that turn people into stone. By staring at her eyes you can turn quickly into stone due to her being so ugly. We could use the ender men thing and change it to instead of a wierd staring contest to INSTANT DEATH. When staring at the head with cross eye you quickly die making battle with her hard.

Winning the battle
Medusa would be a very fast mob and would be dangerous but there would have to be a weakness for such a strong mob. The Ender Dragons weakness is destroying the crystals and the Withers is by a lot of ways. Hers could be using a pumpkin. Like endermen staring at them with a pumkin makes them not attack so maybe staring at Medusa with a pumkin makes you not turn to stone. After being stared at with the pumkin she will attack with the normal attack of a zombie. Since her true power is in her eyes this would be a good way to win against her without turning to stone. Thing is her hard snake scales would make her have a very strong defence making her on the most armored mob in the game. Still people want a challenge right?