Four beasts. Four giants. Four threats. The first two were super-simians: the Kryptonite-irradiating Titano and a self-replicating interdimensional ape. Then there was the synthetic Shaggy Man and the mutated Marcopidae Gigantis. All four of them possessed tremendous power and bestial instincts guiding them.
Earth-One's Superman had to face the former chimp Toto, now transformed during a flight in a space capsule by Kryptonite radiation and growing large. Emitting green Kryptonite eye beams, the Man of Steel depended on his girlfriend Lois Lane and best buddy Jimmy Olsen to defeat him. Eventually, he was sent to an alien world of giant beasts. Earth-Two's Immortal Man faced multiple manifestations of a mysterious energy ape, which he eventually destroyed by sending it into a rift in space which he then detonated.
Earth-One's Justice League had to deal with the threat of a synthetic entity, developed by a benevolent professor from plastalloy, labeled Shaggy Man that was seemingly infinitely adaptable and thus indestructible. Eventually, Green Lantern saved his fellow Lesguera from this beast who was rampaging aboard their satellite headquarters by shrinking it. Earth-Two's Green Lantern and Doctor Mid-Nite, alongside their best buddy Edmund Blake, encountered the immense Marcopidae Gigantis, in a secluded Australian valley of such creatures. Lantern himself used green beams in the form of boxing gloves to try subduing the beast, until Mid-Nite intervened with some creative ingenuity to cause the creature to flee, never to reappear.