Speed Force (as Joe West): We pretty much invented trippy here.
Beware: Spoilers may follow.
If you were to merely read the title of this episode you would probably assume that there somehow came to be a meta rampaging dinosaur-like creature in Central City. Something like that would be quite crazy for the Flash (but I wouldn’t put it past Legends of Tomorrow to do it). While it doesn’t build up anything for Zoom, it does give something extremely moving.
The story involves Barry (Grant Gustin) journeying through the source of his powers, the Speed Force in attempt to regain his powers and return home. Meanwhile the villainous Girder (Greg Finley) escapes and the team must work to recapture him without Barry.
This was our first introduction to the Speed Force, which is quite interesting in this show’s version of the mythology. In a very effective way it’s shown has its own sentience and can take on the form of anyone it chooses. In this case they take on the form of Barry’s loved ones to make him feel more comfortable. Much like Welcome to Earth 2 it’s fun to see the cast take on these different roles. While they are all playing the same character, they all do an excellent job of building on Barry’s emotional connection to them and driving him towards his goals. This episode is easily one of Grant’s strongest performed as he clashes with the speed force in forms of these people and gradually comes to terms with his mother’s death.
This part of the story reaches its peak when Barry encounters the speed force taking on the form of his late mother. Barry at first keeps his guard up knowing full well this isn’t his mother. But at the end it doesn’t matter whether it’s the speed force or her spirit as it gives Barry the necessary strength in order to come to terms with her death. Regardless, the two sit and read the Runaway Dinosaur seeing the two talk and read the book is downright emotional just through the way day read it.
The team working to stop Girder is more or less a subplot but it does help balance out the episode as a whole. It has a good amount of comedy seeing Cisco and Iris work together take him on. The real problem with this whole thing is that Girder could have been replaced with virtually any metahuman.
The main plot of the Runaway Dinosaur doesn’t advance the villain any further but it does advance our hero in such an emotionally engaging way. Barry may have been without his speed until the end but this episode takes a main plot that would have been something cheesy and around into a heartfelt journey in a flash.