With only three episodes remaining in the season, 'Rick and Morty' chose to ditch the concept of Interdimensional Cable, opting for a similar anthology-style format, but focusing on deleted memories instead of the usual ad-libbed segments. Rick refers to this style as "A clip-show of clips you haven't seen."
What are the mind blowers?
The episode starts with our titular characters being chased by a character that looks like Johnny Depp would play him in a Tim Burton film. As they're running, Morty looks into the eyes of the Truth Tortoise he's carrying and is granted all of the knowledge in the universe (if that isn't the most 'Rick and Morty' sentence I have ever written, I don't know what is).
This overwhelms him, and he asks Rick to erase the knowledge he gained. Rick shows him a room of colored vials (the Mind Blowers), which we learn are memories that Rick has removed, either upon Morty's request or of his own volition. Morty asserts that blue vials are memories that are his fault, purple vials are his family's fault, and the red ones are Rick's. Rick denies this, as the red vials seem to contain him making mistakes exclusively. After both of their memories are wiped, Summer comes into the room and resets them with vials indicated by a card labeled "Scenario 4". Interestingly, the card indicates that a blue vial will reset Rick's memory and a yellow will reset Morty's. Rick being reset by a blue vial lends a small amount of credibility to his claim that they are not color-coded.
Why do they matter?
Had Morty from season one been shown this room (which he probably was), he wouldn’t (and probably didn’t) react the same way. Season One Morty would worry at the existentialism of how easily Rick can control Morty’s perceptions of the world. Season Three Morty, on the other hand, doesn’t care about the grander implications.
The more impulsive Morty we’ve come to know is ready to attack Rick after finding out about the mind blowers. This scene highlights the arc Morty has traveled through the series so far.
In one of the first scenes in which we see Summer in the series, she watches as an individual that Rick froze fall and shatter. Her response to this is to collapse and cry before holding a candlelight vigil.
In this episode, Summer regards the sci-fi antics almost dismissively as she calmly follows the instructions left by Rick and restores their memories. Scenes like this make one wonder how the Summer of season three would react in “The Ricks Must Be Crazy," where she had to rely on Rick’s space cruiser to keep her safe.
As the recurring motif, Rick shows marginal, if any, character development. Despite being a rather static character, we do learn more about his character. In one scene, Rick reprimands Morty for flipping the incorrect switch when he asks him to turn out the lights. Knowing that he will have to erase Morty’s memory, he takes Morty to see that this action resulted in several deaths by interrupting their life support system.
Rick is willing to go through the extra effort of driving Morty to an alien storage facility and then erase his memory just to prove that he is right.
Though these mind blowers don’t advance the plot, they do uniquely showcase the characters.