The AGX-11 Over.on was a next-generation mobile suit conceptualized by Paptimus Scirocco in late U.C. 0087, envisioned as part of his plans for the post-Gryps War era. It was designed together with the PMX-004 Titania in January U.C. 0088, and was described by Tonio Oaks as “a Gundam-type version of The-O.”
The entire MS was initially covered in Chobham Armor, which made it resemble The-O. However, after this armor is purged, the main Gundam-type body is revealed. The Over.on is extremely versatile in this form, and was designed to pursue high basic performance. In this form the Over.on can also equip various optional armor parts, such as the Chobham Armor and the PMX-000G Messala Glashtin Mobile Armor.
Personally designed by Scirocco himself, the Over.on was not produced until after Scirocco's death, in U.C. 0089. After defecting to Anaheim Electronics (AE), Tonio provided both the blueprints and the Grimoire System for the unit. Out of technical curiosity, AE attempted to reconstruct and complete the machine. However, the project was abruptly canceled soon after completion, and the Over.on subsequently disappeared. Neo Zeon remnants discovered the Over.on inside a wrecked Columbus-class transport ship in a shoal zone and attempted to reactivate it by forcing a drugged Fiorina Feeley to pilot the unit. However, when the monitor displayed the location of Scirocco (who was actually Mashiro Oaks), Fiorina regained consciousness and took control of the mobile suit, setting course for the Olympus Colony in Side 2. At that time, the Over.on was in its “Armor Form,” its entire body covered in Chobham armor modeled after The O, serving as camouflage that concealed its true identity as a Gundam-type unit.