Down Mario is a Super Mario Bros. 1 ROM Hack created by Beta in 2004. This hack was designed to show off the ability for Mario to warp through vertically (from bottom to top) with two sample levels designed especially for that.
This TAS runs, or in fact, falls through both levels with ease (first on the normal game, then on the hard game) and beats this TAS by Chatterbox (티어) by almost a second.