This story (technically retitled "Krang") is reprinted from TALES TO ASTONISH #14 (1960), a 13-page Kirby/Ayers story featuring one of the classic elements of stories from that era, giant insects. In this case, Professor Carter wants to employ giant insect power, but can't get funding for his formula. He goes to Europe, where a key ingredient can be found, and sets up shop in an old castle where a servant named Ludwig works. Unfortunately, in his greed Ludwig plans to steal the formula and gives an overdose of it to an ant, causing it to quickly grow and gain intelligence.
Krang goes on a rampage trying to get the formula so he can rule an insect army and rule the world. Fortunately Ludwig redeems himself (I suspect the art was meant to show him dying, though the script just has him injured) letting Carter escape and use the formula to come up with a natural foe for Krang.
Very fun story, there's just something about seeing a giant Kirby/Ayers ant running up the stairs of an ancient castle that cracks me up. Definitely one of the better of the monster stories of that era.
Kirby did a new cover for this issue, inked by Klaus Janson, with the usual elements of a fleeing crowd, a monster causing great damage and a hidden menace.