Ike Clanton, from Martian Dreams
In Earp's dream, he was an ornery, charcoal-grey stallion called "Marshall" awaiting to be sold at auction, and Clanton was one of the bidders. When the Avatar asked him about the various horses up for auction, Ike said of the grey stallion, "Don't much like the look in his eye. I imagine some day it'd come down to him or me."
When the Avatar subsequently bid against Clanton for "Marshall" and eventually won, Clanton looked disgusted, saying only an idiot would pay so much. The hero set "Marshall" free afterwards, thus freeing Wyatt Earp from the Dream-World.