I put a lot of titles in Weird-Ass Cover Wednesday because they are unintentionally weird. Howard The Duck's weirdness, however, is completely intentional. Howard was mostly a chance for Steve Gerber to parody pretty much every other Marvel property in existence. Check out the cover text such as "When Bites the Beaver!". It's spot on. Howard The Duck is the comedic ancestor of The Tick.
The best thing about Howard, though, is that he's in official Marvel continuity.
The following covers need no further commentary. They speak for themselves.