Supergirl
What you need to know about this episode:
A breach opening over the Danvers family's Thanksgiving table wasn't the most exciting thing to happen on Supergirl this week. While this episode wasn't very crossover-y, it did not skimp on the action. Cadmus unleashed Medusa (an alien-killing virus created by Kara's father) on the underground alien bar, infecting our beloved Mon-El. In order to distribute the virus, Mama Luther turned to Lena. And J'onn went full-on White Martian to fight the real Hank Henshaw.
Best quote of the episode:
"You asked for stuffing so I ripped my mattress open and brought some."— Mon-El
What had us shouting at the TV:
Kara and Mon-El kissed! Then Kara's mom saved his life, and they just decided to pretend the kiss didn't happen? You're aliens; you're not supposed to take part in senseless human drama.
Our favorite crossover moment:
Other than Kara and Mon-El playing Monopoly during their quarantine? Cyborg Superman had his hands around Kara's throat, and he was taunting her about who was going to rescue her. Then the breach distracted him. Barry is going to rescue her! That's who!
The Flash
What you need to know about this episode:
An alien invasion prompted Barry to bring in the big guns, so our favorite heroes from Supergirl, The Flash, Arrow and Legends met up to defeat the Dominators, who have been abducting humans in an attempt to "understand" their race since the 1950s. Perhaps more importantly, everyone learned about Flashpoint. A superhero version of Mean Girls broke out when the team discovered the implications of Barry's mistake. Oliver and Barry stayed behind while the rest of the team, led by Supergirl, raced to save the president, who was captured by the Dominators. But later Barry and Oliver found themselves facing a new enemy in the form of their brainwashed friends.
Best quote of the episode:
"That's true, he did shoot me."— Barry to Supergirl, explaining Oliver's training methods
Our favorite crossover moment:
Anytime grumpy Oliver and hopeful Barry are in the same room, humor is bound to touch our hearts. Seeing the two original superheroes together again made us nostalgic for a simpler time—but not one without an airplane hanger filled with all our favorite superheroes.
There was also Dig throwing up after Barry whisked him and Oliver away from Vigilante, Diggle's reactions to the timeship and Supergirl's ~superness~, Heat Wave's innuendos toward Supergirl and Sara crushing on Kara. Basically every moment of this episode made us wish that every week could be crossover week.
Arrow
What you need to know about this episode:
In the 100th episode of Arrow, Oliver woke up in a world that he did not recognize. After some of our faves were beamed up in a cliché alien abduction, the Dominators played mind games with Ollie, Thea, Sara, Dig and Ray. In a world where Oliver never got on the Queen's Gambit, he was set to marry Laurel while he faced pressure from his soon-to-be-mayor father to take over Queen Consolidated. While they were trapped, the heroes realized something was off as Cisco, Barry and Team Arrow worked to save their friends from the alternate reality.
Best quote of the episode:
"We need to find Oliver and Company!"— Cisco
Our favorite Arrow 100 moment:
How can we choose from so many standout moments? Thea giving Oliver the "rock" he gave her in the pilot, seeing Moira again, Diggle in the Arrow suit. Although we did love the déjà vu flashbacks too.
Our favorite crossover moment:
Curtis and Rory meeting Supergirl and The Flash was a fangirling moment we could totally relate to.
Legends of Tomorrow
What you need to know about this episode:
In the conclusion of the "Invasion!" crossover event, Nate, Mick, Amaya, Felicity and Cisco traveled back in time to the Dominators' first attack on Earth. When Nate, Mick and Amaya were captured by shady government agents, Felicity and Cisco jumped at the chance to rescue their friends and cure their FOMO. Meanwhile, Professor Stein was confronted with his new daughter, and he revealed to Caitlin that he believes he created his own aberration. The Dominators' mission was finally revealed: they wanted to learn about metahumans and promised to leave peacefully if The Flash gave himself over.
Best quote of the episode:
Felicity: "This ship is…"
Cisco: "…automatic…"
Felicity: "…supersonic…"
Cisco: "…hypnotic…"
Felicity/Cisco: "…funky fresh!"
Our favorite crossover moment:
Cisco and Felicity gushing over the Waverider made us so happy our insides almost exploded with joy.