Astatine is a scrapped Godzilla-Agira hybrid monster and a scrapped Periodic Genesis Kaiju (PGK) created by KoopaGalaxain. Along with Europium and several other unnamed PGKs, Astatine was to star in the second wave of Periodic Genesis Kaiju sprites, before that wave was turned into Periodic Genesis: Dawn of Sepsis.
As befitting her components, Astatine draws similarities from Agira and Godzilla in her design. She has piercing green eyes and light brown skin, along with a pronounced frill on her head. Astatine's arms display increased muscle growth, as Astatine prefers to fight tooth and nail rather than with beam techniques.
As very little is known about what Astatine's role would have been in the proposed second Periodic Genesis wave, it is unknown exactly how Astatine would have been portrayed, or what her personality would be. All that is known is that alongside Europium and the other Wave 2 PGKs, she would have been allies with the PGKs from Wave 1; Caesium, Wolfram, Radium, Boron, Zinc and Germanium. Astatine was originally going to be a close friend of Europium, with the latter intending to defend her at any cost.
- Astatine's nickname, 'The Youngest', comes from the chemical properties of Astatine, an element that has a half life of only 8.1 hours.
- Astatine is the first female PGK.