A new metahuman menace with the power to transform himself into living asphalt distracts Barry and Harry from their new plan to seal the breaches between Earth 1 and Earth 2. Meanwhile, Iris - determined to do something about Wally's drag-racing - places herself in danger in an effort to save the brother she's just getting to know.
The Flash comics of Geoff Johns (creator of Tar Pit) and the New 52 Flash series (Wally West as a juvenile delinquent Iris is trying to scare straight).
Calling the final fight with Tar Pit anti-climactic is putting it mildly.
Tom Cavanagh does some great silent acting here as we see Harry pondering his betrayal of Team Flash throughout the episode.
For the first time, Wally West is given time enough to be something other than the reluctant son/brother and Keiynan Lonsdale develops the character wonderfully in these moments.
The special effects during the sequence where Barry rescues Wally but doesn't quite rescue Iris are wonderful.
Barry displays his gift for speed reading twice in this episode, managing to read everything he needs to know to catch up to Harry's expertise regarding CFL Quark Matter in seconds. However, Barry can only retrain this knowledge for about half an hour and requires refreshers to keep the knoweldge in his short-term memory.
In the comics, Tar Pit was a man named Joey Monteleon. The younger brother of crime-boss Jack "The Candyman" Monteleon, Joey got involved in the family business but was sloppy about his work. He was imprisoned but was confident his family's connections would get him out. He was wrong. Six months later, Joey turned to meditation to calm himself and discovered a metahuman ability to astral project his mind into inanimate objects. He enjoyed "joyriding" until he made the mistake of placing his mind inside a vat of tar and got stuck.
Luckily - for Joey, at least - he discovered he could shape the tar into a humanoid body and that his new form made him virtually invulnerable, extremely flexible and gave him the ability to project intense heat as well as toxic fumes. He was also able to disguise himself as a road by flattening himself against it.
The DCTVU version of Tar Pit seems to have the same powers listed above. His origin, however, is completely different. No reference is made to Joey Monteleon's family and Joey is said to have spent most of his youth living in a juvenile detention facility. The biggest difference, however, is that Joey gains his powers after being dropped in a vat of tar just before the STAR Labs particle accelerator explosion.
Barry's first fight with Tar Pit ends after he tricks Tar Pit into breaking a fire-hydrant. This gambit has been used against a variety of super-villains in comic book history - usually electricity and fire manipulators as well as beings like The Sandman or Clayface who are made of material that can be dispersed or diluted by water.
Tar Pit's appearance just before being frozen by The Flash - a giant monster - is based on the character's appearance in the comics.
Tar is not just used in roofing. It is also used in the manufacture of medicines and flavoring for candy and liquor.
Scramjets are a supersonic unoxygenated vehicle. They are able to move faster than conventional aircraft because they lack the weight of the liquid oxygen used to fuel traditional propulsion.
Using Eobard Thawne's research and the brain sample he took from The Turtle, Harry Wells constructs a device that - once attached to The Flash's suit - will allow him to harness Barry's speed and slowly drain the Speed Force energy from his body.
Harry notes that Earth One has yet to create CFL quark matter.
Joe comments that Tar Pit's first victim looked like he was dipped in a volcano. Barry confirms that the depth and uniformity of the burn pattern is something you'd see if a body had been submerged in something like lava but with a lower burn temperature and an added chemical characteristic. Joe adds that there was no secondary accelerate - which Barry notes would not be unusual in the case of a metahuman attack.
The helicity of a particle is left-handed if its spin and motion is opposite.
Cisco and Caitlin determine that Tar Pit's first victim died from suffocation, despite his burns and that there were metahuman particles in the oil left on the victim's body. Cross-referencing O^2 levels in the organic matter, they find a direct match to animals trapped and preserved in an asphalt seep. In essence, the first victim was fossilized.
Cisco and Caitlin suggest Barry can defeat Tar Pit by reducing his temperature, since the viscosity of asphalt lowers as its temperature lowers, before hardening completely.
Barry theorizes that the solution to permanently closing the breaches lies in the electromagnetic insulator of the quark matter.
Harry constructs a breach implosion reactor that can permanently seal a breach after being thrown through it.
Harry also builds nitrous grenades to neutralize Tar Pit. Each one has ten times the concentration of the average hot rod's nitrous tank and they are triggered by extreme heat - 650 degrees. This is the temperature at which asphalt boils.
Caitlin calculates that Barry has lost 2% of his speed following Harry's planting his device on The Flash costume.
Caitlin says that Harry's leeching Barry's speed resulted in chromosomal damage that could have permanently removed Barry's powers.
Cisco: Did I just make metahuman Tinder?
(As Cisco pulls up a record on who Tar Pit is based.)
Cisco: And there it is! Who's the best hacker in the world, people?
Caitlin and Barry: (in unision) Felicity Smoak.
Cisco: What is wrong with you two?! That's not friendship!
Barry: Look, I know that this has been hard for you. But you're not in this alone -
Harry: Yes, I am. As much as you all want me to be part of your team, that's never going to happen! I'm always going to be a father first. And one day, Zoom is gonna make me choose between you and my daughter and every time, unblinkingly, unflinchingly, I will choose my daughter. I will betray you.
Barry: That's binary thinking. It doesn't have to be either/or.
Harry: Life IS either/or! Yes/No! Black/White! Love... Hate. From the dawn of time to this moment right now.
Barry: I guess I just have more faith in you than you have in yourself.
Joe: Look, I know you just lost your mother. And you just found us. It's been like a whirlwind. Now, I can't tell you how to live your life. But I can tell you this. You are not alone. You have people that sit up at night worried sick about you and they're not going to stop worrying about you. That's what a family does. They put up with each other. And we put each other first. Before ourselves.
Wally: So you're not mad at me?
Joe: For being reckless with your life? Yeah. Hell yeah, I'm mad at you! But I'm more mad at myself for being something I'm not. I'm not your friend, Wally. I'm your father. I'm your father. I ain't letting you go.
(Joe's phone goes off. He picks it up and looks at it.)
Joe: It's Barry.
Wally: Go. I'll stay with her.
Joe: You're sure?
Wally: Well, she's my sister, right?
Joe: (slapping him on the back) That's my boy.
(After Joe punches Harry and throws him into a cell in The Pipleine)
Caitlin: Why did you put him in there?
Joe: Because if I didn't, I would have killed him!
Barry: You know, it's ironic? I was just saying how much you remind me of the old Wells. And now here we are, just like I did with him, standing on either side of this glass with me asking you "Why?"
Harry: I'm doing what I have to do to save my daughter.
Barry: Yeah, at any cost, right? At the cost of Joe's daughter?
Harry: I told you I would betray you. I told you I would have to choose!
Joe: You choose wrong.
Harry: Really, did I? Because I just sacrificed my daughter. Because I just sentenced my daughter to death to save your son!
Joe: You want a pat on the back?
Harry: I want you to send me home!
Wally: Growing up we didn't have a lot of money to go to the movies or buy toys. Instead she would just take me in the car and we'd go for these long drives. Just her and I and her music. I remember being on the road with her and just... watching the scenery flash by and feeling so happy. And now when I race... feeling that rush of speed, it's like... it's like I get to go back to those days. I didn't want to stop because, if I do...
Joe West's father was a police officer as well.
As a child, Wally wanted to be an astronaut when he grew up. Reportedly, so did Barry.
We find out the sample Harry took from The Turtle's body in 210 was of his brain tissue.
The expression "Two heads are better than one." may only exist on Earth One. It is possible, however, that Harry is just being difficult when he says he never heard that before.
Wally's street-racing nickname is Tail Lights, because that's all the people racing him see of him.
A radio news bulletin at Diamond Detailing mentions Oliver Queen's mayoral campaign - an on-going plot-thread in Season 4 of Arrow.
Barry refers to Patty's departure in 211.
Cisco develops a new app that monitors all the news and social media in Central City for rumors of metahuman activity.
Joe refers to when he first confronted Wally on his street-racing in 210.
Barry's usual average speed is 1500 mph. During the first fight with Tar Pit, when Harry first started draining his speed, his average speed was 1450 mph.
Iris is not allergic to flowers.
Barry refers to Cisco's revealing his secret identity to Snart in 116.
Francine West apparently died sometime within the past week, off-camera.
The Fridge Factor
Iris doesn't come off as the tough Lois Lane figure the writing is trying to turn her into in this episode. Partly due to Candice Patton's performance (she doesn't play tough convincingly, I'm afraid) and partly due to the fact that it's been so long since we've seen Irish doing any reporting work, much less serious investigative reporting. And she's injured in order to give Barry, Joe and Wally more motivation to do what they do.
The Bottom Line
Tar Pit's a bit lackluster as a villain and while I'll give them credit for trying to give Iris something to do, it's been so long since we've seen her doing any reporter work that thrusting her into the Lois Lane role this week seems truly forced. It's also problematic when Iris' injury serves as a call to action for three male members of the cast. The subplot with Harry saves it, however and the whole thing is just inoffensive enough that it manages to be mediocre overall.