The Aloadae (or Aloadai) were Otus and Ephialtes (or Ephialtis), sons of Iphimedia, queen of Aloeus, by Poseidon, whom she induced to make her pregnant by going to the seashore and disporting herself in the surf or scooping seawater into her bosom. From Aloeus they received their patronymic, the Aloadai. They were strong and aggressive giants, growing by nine fingers every month[3] nine fathoms tall at age nine, and only outshone in beauty by Orion.

The brothers wanted to storm Mt. Olympus and gain Artemis for Otos and Hera for Ephialtes. They would have piled Mt. Ossa atop Olympus, then Mt. Pelion upon Ossa, but were killed by Apollo before their downy beards had even sprouted, and bound to columns in the Underworld.

According to another version of their struggle against the Olympians, alluded to so briefly that it must have been already familiar to the epic's hearers, they managed to kidnap Ares and hold him in a bronze jar, a storage pithos, for thirteen months, a lunar year. "And that would have been the end of Ares and his appetite for war, if the beautiful Eriboea, the young giants' stepmother, had not told Hermes what they had done," Dione related (Iliad 5.385–391). He was only released when Artemis offered herself to Otus. This made Ephialtes envious and the pair fought. Artemis changed herself into a doe and jumped between them. The Aloadae, not wanting her to get away, threw their spears and simultaneously killed each other.

On a more positive front, the Aloadae were bringers of civilization, founding cities and teaching culture to humanity. They were venerated specifically in Naxos and Boeotian Ascra, two cities they founded.

Ephialtes (lit. "he who jumps upon") is also the Greek word for "nightmare," and Ephialtes was sometimes considered the daimon of nightmares.