Dagon

Dagon, known to the Japanese as Raijin (雷神 Raijin), is a member of Godzilla's species that first appears as a skeletal corpse in the 2014 Legendary Pictures film Godzilla, and is explored further in Godzilla: Aftershock, the official graphic prequel novel to Godzilla: King of the Monsters.

In the 11th century, B.C., a group of Phoenicians made their way to the Japanese islands, where they encountered a gigantic creature which they believed to be their god Dagon. They witnessed a battle between Dagon and the entity the Japanese called Jinshin-Mushi, in which Dagon was defeated and infected with his enemy's parasitic young. The Phoenicians witnessed Dagon regain consciousness and return to the sea, and while they assumed that he lived on, he eventually collapsed and died in the Philippines. His skeleton was unearthed in 1999 A.D., unleashing the two MUTO spores which had incubated inside of him. Godzilla, another member of Dagon's species, managed to fight and kill both MUTOs in 2014 before they could reproduce, and later slew Jinshin-Mushi when it emerged to try and implant its larvae inside of him.

Godzilla (2014)
In 1999, miners in the Philippines uncovered a radiation pocket underground. Believing they had stumbled upon a valuable uranium deposit, they continued digging until the entire mine mysteriously collapsed into a massive underground cavern containing the skeleton of an unidentified Titan. Monarch dispatched Dr. Ishiro Serizawa and his assistant Dr. Vivienne Graham to inspect the cavern. Dr. Graham recognized the structure of the skeleton and asked Serizawa if it was possible this skeleton belonged to Godzilla, but he responded that this skeleton was much older. Attached to the skeleton's ribcage were what Graham concluded were two parasitic spores. One spore appeared dormant, while the other had split open, with whatever emerged from it leaving a trail out of the cavern and directly into the ocean. Monarch later constructed diagrams of this skeleton, labeling it "Species 5146_ADAM" and determining that it was a member of Godzilla's species.