Deliberate mistake: Hank only discovers the tattoo on the back of his head after having his hair shaved off. There is no way, however, he wouldn't have noticed it before this. The tattoo artist had to shave hair off the back of his head before putting on the tattoo. While he might have not realised right away, the pain the following day and the fact that he would have noticed a large part of his hair missing would make it unavoidable.
King of the Hill (1997)
1 deliberate mistake in season 7
Starring: Brittany Murphy, Pamela Adlon, Mike Judge, Kathy Najimy, Johnny Hardwick
Bystand Me - S10-E2
Continuity mistake: While Hank, Peggy, and Bobby are asking for help picking up the papers with the dangerous ammonia and bleach recipe, a person in back of the group they are talking to that was originally wearing a dark red hat, red shirt, and blond hair switches to a pink, light blue shirt, and brown hair. A window also suddenly appears behind this individual, where there wasn't one before. (00:17:49 - 00:18:11)
Peggy: It was like a knife in his heart when she stuck that fork in his back.
More trivia for King of the Hill
To Sirloin with Love - S13-E20
Question: What is Boomhower's occupation?
Answer: Jeffrey Boomhauer is a Texas Ranger as can be seen in the final episode at the end when he sets his wallet down, it flips open revealing a Texas Ranger badge.