When Tony Stark dons his Iron Man armor, Justin Hammer takes control of it and manipulated the Iron Man armor to reveal his identity and place a mind-control collar on him when it turns out that Scott Lang and his daughter Cassandra Lang are his hostages.
When Tony Stark puts on his Iron Man armor, Justin Hammer seizes control of it and uses its features to reveal Tony's secret identity and immobilize him when it is revealed that Scott Lang and his family are in his custody.