The alien is a character played by Daniel Vincent Gordh who appeared in PLAN B. They resemble a Brazingian mind creeper.
Within Jordan Riggs' Inception-ed dream as conducted by Chris and Jack, the alien made a deal with Jack from the Past to release "her" in exchange for a bag of money, before using a bottle-like ray gun device to vaporise Jack from the Past. They teleported away shortly after. (PLAN B)