This Can Be Easily Accomplished In Classic Any/ All.
You Need A Transporter In Your Game As Well To Net This Achievement.
- A Transporter Can Switch You And Your Target, Making You Target Yourself.
Easy Way
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If Someone Said They Are Transporter, Shoot Them A Whisper
- Tell Them You Are Mafia And You Want To Hit Yourself, "So Target Yourself And Me".
Organic Way
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The Any/All Playlist Is Your Best Bet, As You Can Get A Few Transporters In The Same Game.
If You Successfully Get Switched, You Will Forge Yourself And The Achievement Will Pop At The End Of The Game.
Good Luck!