Thee is an old story called "The Mad Moon" by Stanley G. Weinbaum, set on Io, where a human with a deadly ray gun gets into several fights with slinkers, tiny intelligent beings about six inches tall.

Firing a ray gun blast at a single slinker would be like shooting a cannon at a mosquito.  And his ray gun only has a few charges.

He is as huge compared to the slinkers as a giant monster in a monster movie, but movie monsters are usually killed by the tiny, numerous, and intelligent humans in the end.  His ray gun makes him as dangerous as a fire breathing dragon or Godzilla with his atomic breath, but fictional dragons usually get killed in the end like movie monsters do. 

And in the story the slinkers usually have the upper hand vs the human.


http://www.isfdb.org/cgi-bin/title.cgi?47553[1]


  [1]: http://www.isfdb.org/cgi-bin/title.cgi?47553