For a show involving cosmic fungus and a giant tardigrade, Star Trek: Discoveryhas been pretty serious this season.

That's not a bad thing. But Sunday night's episode -- called "Magic to Make the Sanest Man go Mad" -- marked a glorious return to the campy, cheesy version of Star Trek that made other series so much fun.

SEE ALSO:The 'Star Trek: Discovery' episode that changed the universe

This episode had it all: time crystals, a time loop, and a man in a cape. Oh, and plenty of old-school references for diehard Trekkies.

Rainn Wilson, who you might know as Dwight from The Office, holds the episode together. He plays Harcourt Fenton "Harry" Mudd, a con man who features in several episodes of the original 1966-68 Star Trek.

Mudd appeared earlier in Star Trek Discoveryas a Klingon prison cellmate to Capt. Lorca and his new head of security, Ash Tyler. But we didn't really get to see the scheming, chaos-spreading version of Mudd we know and love until now.

In "Magic to Make the Sanest Man go Mad" (a quote from The Iliad, in case you were wondering), Mudd tricks the Discoveryinto beaming a giant space whale into its docking bay. That's where he's hidden his ship, complete with a time crystal modified by a four-dimensional being that lets him start a 30-minute time loop.

If that plot seems strangely familiar, it's because Star Trek: The Next Generationdid something similar in the classic episode "Cause and Effect."

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This time the culprit isn't a neutral distortion in the space-time continuum. It's Mudd, who replays the same scenario over and over, hoping to learn more about the Discovery's spore drive.

The ship explodes each time, and only Paul Stamets (Anthony Rapp), who has transcended time and space by hooking himself into the drive, knows what's going on once the loop begins again.

Even if you haven't watched every episode of every Star Trek franchise, there's still a lot to like here. Trekkies, though, had to be feeling extra excited when Mudd calls Lorca "mon capitan" -- a reference to everyone's favorite wisecracking alien from The Next Generation, Q.

In the original series, Mudd brings Kirk and Spock down to his planet full of android women. That episode ended with the Enterprise crew figuring out how to turn the androids into an army of Mudd's furious estranged wife, Stella.

So it made sense that the Discoveryepisode ends with Mudd reluctancy reunited with Stella. Turns out he had skipped town to the chagrin of her father, Barron Grimes, a powerful arms dealer.

Never mess with a man in a cape.Credit: CBS

In this appearance Stella wears a purple and red outfit that wouldn't look out of place in the 1960s series, while her father wears a leather suit with cape, and holds a cane.

It was a perfectly cheesy ending to a loopy, exciting episode. The time loop shenanigans provided a respite from the larger compromised-captain-versus-racist-Klingons main plot.

Not that we want to return to the days of transporter accidents, mirror universes or holodecks gone awry, but it's nice to see the cast of Discoveryhave a little fun.

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TopicsStar Trek