The arc reactor was created by Tony Stark to power an electromagnet in his chest.
The Mark 1 reactor was replaced with the help of Pepper Potts, who then framed the original the device as a gift for Tony, with an inscription reading "Proof That Tony Stark Has A Heart."
The Mark 1 reactor was replaced with the help of Pepper Potts, who then framed the original the device as a gift for Tony, with an inscription reading "Proof That Tony Stark Has A Heart."