Alcyoneus

In Greek mythology, Alcyoneus (Greek: Αλκυονευς, Alkyoneus, "kingfisher") was one of the Gigantes who waged war upon the gods during the Gigantomachy. As a Gigante, Alcyoneus was born from the blood of Uranus when it fell upon Gaea. He was the father of the Alcyonides.

Mythology
According to Apollodorus, Alcyoneus and Porphyrion were the greatest of the giants. Alcyoneus was immortal and could not be killed while he was in his native land. In order to kill him, Heracles knocked Alcyoneus unconscious (or found him while sleeping) and dragged him out of his native land at the request of Athena. When out of his homeland, Alcyoneus died.

Some sources suggest that Alcyoneus started the Gigantomachy by stealing the sacred cattle of Helios.