The Avengers #37

In "To Conquer a Colossus!", the Avengers face their greatest threat yet when captured by the alien Ixar and his mechanical Ultroids, leaving Hawkeye and Black Widow to break the team free. With Hawkeye bound by his oath not to kill and Black Widow still outside the Avengers' code, their clash of principles could be their undoing. Written by Roy Thomas, illustrated by Don Heck, and featuring a striking cover by Gil Kane, this 1967 classic captures the tension of loyalty, duty, and the cost of survival.