Mobzilla, AKA Bōjira (based on Toho's Godzilla) is the strongest hostile mob in Minecraft, added in the 50.6 update. It only spawns in Ocean and Plains biomes and is not manually summoned, spawning in any level of light. Its arrival is always marked with a massive storm 10x more dangerous than typical ones. Also, for good measure, around 50 Iron Armor Zombies are accompanying him at all times, fending off any players and killing anything in sight. He stands at over 50 blocks high, towering over almost all other entities. Mobzilla is automatically hostile towards every single mob besides his zombies and other spawned minions. Upon spawning, he actively begins to roam towards the nearest player or their creations. There is virtually no hope to defeat Mobzilla and his Zombie Army until the player(s) reaches their maximum power. The best way to kill him is by fighting him with tamed Kaiju allies.
Mobzilla is the second most powerful Kaiju mob in the game. Other Kaiju include Rodan, Mothra, King Kong, Kiryu, Ghidorah, and Gigan. However, one can never be certain that there are no others scattered throughout the world...
He is undoubtedly the second final and hardest boss in Minecraft.
Damage Value: 20 Hearts per kick.
Armor: 80 (equivalent to 4 sets of diamond armor)
Kick/Punch - Standard melee attack, knocks target 2 blocks in the air.
Atomic Breath - Launches a barrage of dozens and dozens of Ghast and Blaze bombs that explode and ignite upon contact.
Thermonuclear Breath - Launches world-ending and crater-creating fireballs that burn, explode, and fry anything hit (average 100 hearts damage per fireball, also equal to Charged Creeper's explosion radius)
Lightning - All players within the immediate vicinity of Mobzilla will periodically be hit with lightning bolts.
Seismic Attack - Tosses all nearby entities 30 blocks into the air.
Lava Breath - Spews lava source blocks in all directions.
Roar - Gives all nearby players a Weakness and Slowness status effect for 20 seconds.
Nuclear Pulse - Sets all nearby players alight until in contact with water.
Super Jump - Used to navigate freely across the map, over 25 blocks max height.
Burning Mobzilla - Upon losing 3/4 of its health, all of its abilities and attributes are increased by 25%.
Vampirism - Selects the player that has done the most damage to Mobzilla and automatically drains 30% of their health and takes it for himself.
Animate - Used periodically to summon one of every other mob in the game (not targeted by Mobzilla.)
Only one Mobzilla can spawn in the world at a time (spawnings spaced out by at least 10 Minecraft days)
Incredibly advanced and superior Artificial Intelligence
No fire damage
No fall damage
Moves extremely fast in water
Sinks to the bottom of water masses unlike other mobs
Destroys terrain in its way
Destroys layers of player-made blocks when stepped on
Super Regenerative Powers (5 hearts per second)
Self destructs on death, killing everything around it (10 second warning marked by glowing, roaring, and explosion particles)
Becomes stronger when in contact with water or lightning
Total hostile mob spawning increases by 50% whenever Mobzilla is active
All Redstone signals within 500 blocks of Mobzilla are completly disabled (this includes redstone dust and other accessories)
Drops on Death
64 Mobzilla Scale - Used to craft strongest armor in the game, Mobzilla Scale Armor
2-5 Mobzilla Claw - Used to craft strongest sword and bow in the game
128 Mobzilla Tooth - Substitutes as 5x more powerful arrows for bows (compatible with Infinity)
4-6 Mobzilla Dorsal Fin - can be combined with any armor piece to add Thorns V enchantment (does not accelerate breaking rate)
25% chance to drop Mobzilla Skull Trophy
A sizeable bounty of tons of blocks of Emerald, Diamond, Iron, Gold, Nether Stars, or even Dragon Eggs
Several various Enchanted Books
1 Space Mobzilla Spawn Egg
Punch bows (extra damage)
Looting swords (extra damage)
Potions of Healing/Regeneration (acts as poison)
Aqua Affinity helmets (thoroughly protects wearer from Mobzilla damage)
Golden Swords (deal 25 hearts of damage to Mobzilla but still break easily)
These Kaiju will attempt to move towards Mobzilla to protect and fight alongside him. It is best to hunt down these Kaiju individually before they can combine forces and become even harder to kill.
An even more powerful variant that does not count as another mob is Space Mobzilla, who is even more deadly and harder to kill. It has all the same stats and attributes as normal Mobzilla, only multiplied by 5. Upon death, Space Mobzilla drops twice the loot as his counterpart.