I once worked with a guy who did the opposite of this. He just randomly mentioned that he had a twin brother one day, which no-one believed given how long we had all known him. But he persisted by casually talking about him in regular conversation. Nothing overly noticeable, just enough to plant the idea in people’s mind that he did indeed have a twin brother. Around the same time he started growing his beard out and really made it his personality for several months to be the guy with a beard. It all came together one day, he finished his shift around lunch time and left like usual with his glorious beard. Unbeknownst all but a select few of us, he hadn’t actually left. He left the store and drove his car around the corner to the other car park then used the sink in a nearby public toilet to completely shave his beard off and changed his clothes. Then he just walked in through the front door, introduced himself as the name he had been using for his fake twin brother and asked if his brother was there. He always had a reputation as a joker, but I don’t think any of us truly believed anything he said after that. Not that he cared. It still cracked him up years later when folks were telling the tale to the newbies.