Star Trek: 10 Most Shocking Returns
2. Wesley Crusher (Star Trek: Prodigy Season 2)
When Wesley Crusher returned in Star Trek: Prodigy's second season episode The Devourer Of All Things Part 1, he revealed himself as a time traveller. When attempting to trace his lifeline, there is simply no better way to understand him than as a man out of time, wearing only the finest of jumpers.
Technically, Wesley returned first in Star Trek: Picard's second season finale Farewell, picking up Kore Soong (presumably before beginning her shift in The Pitt). Wil Wheaton also returned in Star Trek: Lower Decks, in the fourth season finale Old Friends, New Planets, though in that case he was reprising the role in a flashback.
Other Wesley Crusher's have appeared through the years (including an enigmatic 'Crusher' in OTOY's 765874: Unification short film), yet it was in Prodigy that he received the greatest chance to shine. He was described by that show's creators and writers as the original prodigy in Star Trek, so having him appear on the show was a must. Having him appear as this particular version of the character was simply the most logical move forward while time was circling them all.
It is also no mere cameo. Wesley is a supporting character in the show's second season, appearing right through the finale, wherein he even gets the chance to meet his mother (and brother) before disappearing off into the winds of time again.
This was fan service done correctly, logically, and with extremely entertaining payoffs. We're still waiting for that Wesley and Kore spin-off, mind.