My intel included reports of giant alien robots, hidden among us. So I figured -- fight fire with fire, right? 
History
Tony Stark created this armor when he heard rumors of giant alien robots hiding out on Earth. It was Transformer-sized and made specifically for combat with them. The armor wasn't fully combat-ready at the time it saw action. It had severe energy management issues. Specifically, it was extremely energy intensive and ran low on power quickly. Additionally, it was prone to overload if power was supplied from an outside source. Nevertheless, it served Iron Man well in his confrontation with Decepticons, but was ultimately beheaded by Megatron. Iron Man then exited the over-sized suit and continued combat in his Extremis Armor.[1]
Properties[]
The armor was crafted carbon nanotube transistors, printed on silicon wafers and was powered by fifteen amperes.[2]Trivia
After the battle, Tony Stark began designing the next Anti-Transformer Armor wondering if it could be made even bigger.