Gammara

Gammaras are Robotic Turtle-like mobs found in Strongholes and Mountains in AMPLIFIED mode.

Tactics
Gammaras are 3x bigger than an Iron Golem and stronger. They can kill one with one hit or a Diamond Golem by three hits. Gammaras are very strong and can be a boss when you spot them. They are extremely hostile and Using an Emerald Pickaxe on it 12 times will kill it. When it reaches its half health, they changes to brown and gain scratches and the eyes become yellow to red. When destroyed, they explode and spawn three Iron Golems and drops 0-1 Emeralds and 0-3 Diamonds.