Earth Invader

by Randall Garrett

Vintage Sci-Fi Series

From the back cover:

"THE NIPE
The world was gripped in terror when the Nipe, a lethal, alien fighting machine, crash-landed on earth from outer space and began a nightmarish rampage of slaughter and destruction.

THE SUPERHUMAN
Unable to stop the deadly, intelligent creature, scientists quickly developed a plan to turn an ordinary earthen into a superhuman with powers enough to conquer the monster. As the man chosen for the dangerous mission, Bart Stanton was not sure he wanted to give up his humanity."

Earth Invader (1982) by Randall Garrett - Leisure Books