The Imposter was seen in the episode, "Dan", where he temporarily stole Dan's identity.
He is arrogant, persistent, and overbearing and seems to show little remorse for his actions. Besides his identity theft, however, he seems to be a kind man, and even cleans Dan's apartment for him. Mr. Mumbles seems to like him, though this may be due to him looking like Dan.
Later on in season two, he reappears in "The Telemarketer " as such in his plot to harass Dan to the point of madness. He is said to call the titular character every five minutes and is not revealed until Dan, accompanied by Chris and Elise, arrive at his worksite (one Chris had partaken in work as well before its own outsourcing.) Here the imposter seems slightly more sociopathic than his previous appearance in the show. This may be due to spending the last six months in prison.
Later, Elise happens upon his 'home address,' later revealed to be apartment residing over his own, in which he keeps a single phone, a trap door, and the means to release high amounts of sleeping gas. It is shown once again his ability to infiltrate Dan's home. This was also alluded to earlier in the episode when the imposter hid several cell phones in both Dan's apartment and car.Here, we see the imposter now donned in a cat suit vaguely similar to Mr. Mumbles. This appears to be another display of abnormality in his mental state, but was most likely just another method of having Dan sound even more deranged than ever when he recounted the tale.
Also in this episode, we see him wearing Chris's clothing and impersonating him for a few moments. At the end of this episode the imposter achieves his goal and seems to have retired to a lakeside cabin in the forest. However, Dan said he's spending six weeks in prison, unlike him when he spent longer (six months). He may not be happy about that. It means his goal is not yet achieved, or at least not completely.
- The Imposter spends six months in jail just for the real Dan for missing a court date, while Dan spends only six weeks in prison for acting crazy.
- Chris was pretty upset after seeing him go when he got arrested because unlike Dan, The Imposter treated him well.