"But, wait… I thought she was dead?"

Those were the first words that popped into my head when I learned that Caity Lotz would be back as Sara Lance in "Legends of Tomorrow," the new CW superhero series spinning out of both "Arrow" and "The Flash." But last night's episode of "Arrow" put those questions to rest, bringing Sara back to life thanks to a quick dip in the Lazarus Pit at Nanda Parbat.

It was also the last Lazarus Pit appearance (at least for now) thanks to Sara's former lover, Nyssa al Ghul, who sabotages the pit using her late father's secret means. From here on out, no one else can emerge from the resurrection pool, which is a nice fix for the future drama of the series.

Sadly, it's also the end of one of the most popular "Arrow" fan theories — unless that theory was already underway.

The theory centers on Tommy Merlyn, played by Colin Donnell throughout the first season of "Arrow," right up until the character's death, a casualty of daddy Malcolm's plan to raze parts of Starling City to the ground. It was a brutal and tragic ending for a surprisingly lovable character — and only surprising because entering "Arrow," many people expected Tommy to be less Tommy and more Merlyn, one of Oliver Queen's most infamous villains in the comics.

Apparently, that adversarial role went to Malcolm, not Tommy, even if he had his share of beef with Ollie from time to time. But in the end, he died a heroic death, and has since returned only in flashbacks.

But there have been reasons to believe that Tommy could emerge again in the present timeline, albeit as more of the monster we first thought he might be. That's largely thanks to the existence of Lazarus Pits, introduced alongside Ra's al Ghul in season three, equipped with the power to heal wounds and restore the dead.

The pit was used on Thea Queen, Malcolm's secret daughter, and he was wildly opposed to the idea, swearing that she would not be the same as who she was when she emerged. We've seen that bear fruit recently, with Thea's anger management issues needing such professional help that she's back in Nanda Parbat seeking her loathed father's advice.

"You need to feed the impulse," Malcolm instructs her, basically saying that if she goes around mass-murdering for a few days, she'll feel all better… right until she has to do it all over again.

Sounds like someone who is intimately familiar with how loved ones react to the Lazarus Pit, right? It's an interesting bit of insight coming from someone like Malcolm, known to make impulsive and emotional decisions in the moment that he very much regrets further down the road.

The theory, then, is that Malcolm at some point used the Lazarus Pit on Tommy, bringing his son back to life, resulting in some sort of monstrous offspring — somewhere between Thea's current rage levels, and Sara's zombie-like state. It could be a way to subvert the subversion, of Tommy as Ollie's best friend, not his nemesis — until the reborn Tommy returns with that Merlynesque mean streak.

Both Colin Donnell and "Arrow" get along famously, evidenced by the actor's numerous flashback appearances since his character's demise. It's not a matter of not wanting to work together. If there's a good story in place, you can easily see a Tommy resurgence. And there is a good story in place… but now, thanks to Nyssa destroying the Lazarus Pit, it has to already be in place.

Tommy has to be off in the world on his own "island" of sorts, running through his own crucibles, becoming someone worthy of going up against (and hopefully, one day, teaming up with) Oliver. If Malcolm hasn't already submerged his son in Lazarus? Then the fan theories that Tommy's going to come back some day aren't going to hold much more weight, sadly.

For my part, I choose to believe Tommy's kicking around out there until definitively proven otherwise. In fact...

...anyone else think the grave Oliver is looking at is either Tommy's, or someone else's thanks to the secretly alive and evil Tommy? "I'm going to kill him," Oliver says when he stares at the grave. This could get interesting...