It's … [ barry doesn't really know what it is. it's become such a part of him now he thinks of it as another limb. ]

[ he lifts his shoulder, face scrunching up in uncertainty. ] I guess? It's science, too. I kind of got hit by lightning and the particle accelerator explosion, which I guess messed with my cells, and now I can do … that. Run super fast. It's great, but it can be kind of boring at times since I do things really quickly and — [ breathe, barry. ] Sorry if it spooked you. I just didn't want you to be stuck in the tree.