From Hard Drop Tetris Wiki
The Dubble Opener is a meme opener presumably made by stickmancomic (according to smolfeesh) and showcased by smolfeesh on April 1st, 2022. This opener can always be made (assuming you are able to use 180 spins) and like the opener suggests, clears 2 lines. Although impractical, this opener has some merit, countering Perfect Clear openers due to its short build time. It also saves I, which can be used to counterspike. Ironically, it has a chance to perfect clear in 4 lines, but is very unlikely.
Setup
The Dubble Opener can be preformed with any bag. Note that in games where all-spin is rewarded, you'll be likely to get a S, L, or J spin.
The mirror of this opener can be used, but is not worth learning because the original version will always have a 100% build chance.
Perfect Clear Solution
Although very unlikely (2.86%), Dubble Opener does have ONE 4 line solution.