The description indicates we'll be seeing more meta-humans on the series -- for this episode, it's Tar Pit, who fans may remember from Geoff Johns and Scott Kolins' run on "The Flash" -- as well as a deviant Wally West (who seems to like the idea of speed...)
Here's the full summary for Season 2's "Fast Lane":
WALLY FLIRTS WITH DANGER — Barry (Grant Gustin) teams up with Wells (Tom Cavanagh) to figure out a way to close the breaches, but they are distracted by a meta-human nicknamed Tar Pit (guest star Marco Grazzini) who can transform into liquid asphalt. Iris (Candice Patton) is concerned for Wally’s (Keiynan Lonsdale) safety after she finds out about his drag racing hobby. When he refuses to stop she makes a bold move that puts her in danger. Rachel Talalay directed the episode with story by Brooke Eikmeier and teleplay by Kai Yu Wu & Joe Peracchio (#212). Original airdate 2/2/2016.