What's your favorite vehicle with an odd number of cylinders?

Question time! Post your favorite and a brief description of why it's your favorite.

I saw an article the other day that had a comparison of a bunch of vehicles and, like they always do, they added up all of the stats of the cars. One of the stats listed was that there were 99 cylinders as part of the competition. I started thinking about it and it dawned on me that there had to be at least 1 vehicle with an odd number of cylinders. Then I started thinking about all of the cars that had odd number of cylinder engines, a few came to mind but not many.

Anyway, I thought it would be fun to see what everyone came up with as their favorite. I took the easy one, sorry if this is your favorite too. This is completely subjective and can be any kind of vehicle, not limited to cars and trucks. A few words on why it's your favorite can't hurt either.