Star Trek: 10 Most Shocking Returns

3. The Guardian Of Forever (Star Trek: Discovery)

Few expected to see that glorious arch again in Star Trek, especially after nearly fifty years between appearances. However, the booming voice of Bartell La Rue was heard once more in Star Trek: Discovery's third season episode Terra Firma Part 2. The Guardian, or Carl as they now like to be known, had moved planets and timelines to find a nice quiet spot for themselves to get away from it all. That is, until Michael Burnham and Philipa Georgiou popped by for a visit. 

With the third season onwards of Discovery set against the backdrop of Temporal Wars and interstellar Burns, the Guardian was the perfect foil to get around iron-clad laws. Georgiou was dying - horribly - while there was nothing Starfleet were legally able to do about it. Thankfully, the Discovery itself (with a little help from the Sphere Data) managed to identify a way forwards (or back.)

First appearing as Carl, a fairly enigmatic and relaxed man in a bowler hat, the Guardian didn't reveal their true appearance until the story was nearly at a close. Thankfully, this was no mere nod to the past. The Guardian's previous appearances were alluded to, including a quick sentence explaining that any past changes had been allowed as long as the travellers cleaned up after themselves. The temptation it offered to Temporal agents was too strong, so it went into hiding.

The music swells and the vocals boom and in that moment, it was like Kirk, Spock, and McCoy were facing one of their toughest missions once more.