Kamoebas

Kamoebas (カメーバ, Kamēba) is a giant mutated turtle monster that first appeared in the 1970 Toho film Space Amoeba and was incorporated into the Godzilla series in Godzilla: Tokyo S.O.S. in 2003.

Appearance
Kamoebas looks like a gigantic dark blue spiky turtle. Kamoebas is 10 meters tall, 20 meters long, and weighs 28,000 tons.

Origins
Kamoebas was a type of large turtle native to Selgio Island called Megalo matamata, or a rock turtle. Kamoebas was possessed and mutated by the alien amoeba Yog as part of his plan to invade Earth.