The Star Trek Character You Didn't Know Was Written For Robin Williams

There have been many different "Star Trek" series on the air since the original series debuted back in 1966. As such, a number of surprising celebrities have appeared in one way or another in the ongoing universe created by Gene Roddenberry. Dwayne Johnson appears as the Pendari Champion on the "Star Trek: Voyager" Season 6 episode "Tsunkatse." Elsewhere, "Frasier" alum Kelsey Grammer shows up as a fellow Starfleet captain on "Star Trek: The Next Generation," Season 5, Episode 18, "Cause and Effect." Legendary director David Cronenberg shows up throughout "Star Trek: Discovery" Seasons 3 and 4 as a Federation official named Kovich. 

The "Star Trek" universe is so large that these kinds of appearances help flesh out the lore in the beloved franchise, as well as being fun Easter eggs for fans to spot. Of course, some of them are a little more obvious than others; we'd Johnson's raised eyebrow anywhere.

All of this is to say that getting famous stars to appear on "Star Trek" is not a new thing. In fact, one of the biggest actors in Hollywood was meant to briefly appear on "The Next Generation" back in 1991. Comedy legend Robin Williams was an outspoken fan of the science-fiction show, to the point that he even jokes about killing Spock on "Mork and Mindy." Turns out, the writers of the "Star Trek" series had a surprising character in mind for the star.

On "Star Trek: The Next Generation" Season 5, Episode 9 "A Matter of Time" (via IMDb), the Enterprise is visited by a historian from the future named Berlingoff Rasmussen, and he claims that he's there to watch the crew attempt to save a dying planet. However, the Enterprise crew quickly realizes Rasmussen is stealing technology from the ship, like Tri-Corders and Phasers, in order to travel back to his own time — the 22nd century — and pretend he invented them. 

According to the official "Star Trek" site, this is the character Robin Williams was intended to play. Rasmussen is a charismatic, always-grinning con man for most of his screen time in the episode. It's clear the actor's signature energy would've been perfect for the role. Unfortunately, he was unable to join the Starship Enterprise, however briefly, because he was still working on Steven Spielberg's 1991 family adventure, "Hook," where he plays an adult version of Peter Pan.

"Hook" was released in December 1991, which means at least a portion of the filming on the project was still taking place earlier that year. We also know that this Season 5 episode of "The Next Generation" Williams was eyed for aired in November, but filming was likely also taking place around the same time — early 1991. Given the scheduling conflict, the comedic actor never beamed onto the Enterprise.

Williams' replacement, Matt Frewer, brings an incredible flair to the role and really has fun with the time-traveling ne'er-do-well. If Frewer looks familiar, that's because he's got a huge filmography. According to his IMDb profile, he's starred in everything from Zack Snyder's "Watchmen" to "Orphan Black" to "Altered Carbon" to "Fear the Walking Dead."