One of Godzilla's most bizarre foes, Hedorah debuted in the equally bizarre Godzilla vs. Hedorah. Hedorah is an alien organism that feeds and grows on pollution. Naturally, Earth is a buffet to this creature, and it goes on a rampage, sinking ships and attacking factories. While he looks like a giant blob of sludge with eyes, Hedorah is actually a collection of living minerals, each with a life of its own, that can combine together to form one large creature. To this day Hedorah remains one of Godzilla's most challenging opponents, and this is because Hedorah has a nice variety of offensive and defensive abilities. Godzilla's punches go right through it, making hand to hand combat near impossible. It is also immune to Godzilla's atomic breath, which is his most powerful weapon. Hedorah is a shape shifter, allowing it to travel in any environment. Its body is comprised of sulfuric acid, which it can shoot out at high velocity or spray like a fine mist, the results of which are actually pretty horrific. Oh yeah, it also shoots lasers out of its eyes. Is there nothing this thing can't do? This monster was so difficult for Godzilla that it took the combination of his own perseverance and human ingenuity to take it down. Hedorah helped usher in the era of Godzilla as a superhero, and whether you enjoy this interpretation or not, there is no denying this era's importance in establishing Godzilla's popularity. Hedorah may not have reappeared as often as some other monsters in the Godzilla series, but its heavy-handed environmental origins, along with the genuine challenge it gave our favourite radioactive dinosaur, make it quite the monster.