Catfish
(2010)

The film tells the story of a man named Nev, who befriends a little girl named Abby after she emails him a painting. Abby is supposedly a child prodigy who paints beautiful pictures, and as Nev (filmed by his brother, Ariel, and a friend of theirs) becomes better friends with Abby, he meets Abby's older sister, Meghan, and their mother, Angela over Facebook. As he becomes more and more romantically involved with Meghan via IMs, texts, phone calls, and the like, little details start to go awry: Meghan, a supposed songwriter, didn't really write all the songs she said she did, and various other things about her turn out to be untrue.

Finally, the large twist at the end is that Nev and his friends are in the midwest, so they take a side trip and go to meet Meghan and her family, to find that Angela is the only one of the three who is real. The other two were personae created by Angela, who is married and takes care of two disabled sons. She is also the painter of all of Abby's paintings.

Thanks Sam!