Uncanny parallels

There's an episide of Star Trek: Deep Space Nine from 1997 which has got the Mandela Effect community buzzing.

It's called "In The Cards" , and the reason for all the fuss is the story not only involves alternate timelines, where characters appear and disappear into reality, but also made a huge alarm bell ring when a device called a "Bajoran Mandala" was mentioned.

This isn't the first time Star Trek has been associated with the Mandela Effect - the most famous one is Kirk never saying "Beam me up, Scotty"  as well as the one involving Picards Crystal.

At the end of the show, the Mandela Effect is actually described in the form it's understood today, saying that a character had "been inserted into our timeline".

Baseball card

The plot begins with the son of the stations commander, Captain Sisko, who is called Jake, deciding he wants to cheer up his father by buying a Willie Mays baseball card at auction. He then becomes involved with the person who out-bids them for it, who it turns out has the equipment necessary to manipulate the time streams, and at one point disappears himself.

From then on, the various politics of the ongoing diplomatic war negotiations with The Dominion get involved, but ultimately the existence of Willie Mays himself in the timeline becomes an issue.