Lisa, the horrifying ghost from last month's P.T. (the playable teaser for the upcoming Silent Hills) will make a very special appearance in Metal Gear Solid 5: The Phantom Pain, as demoed at the Tokyo Game Show.
She's clearly visible in the YouTube clip above, taken from a demo of the game. Snake uses a device (labeled "active decoy") that basically summons her as a distraction. Naturally, she proves effective: Snakes opponent's are rendered dumb by her seven-foot-tall, eye-gouged appearance.
Later in the clip, the demonstrator sets up a row of three Lisas, and uses one to scare off a curious wolf pup.
Both P.T./Silent Hills and Metal Gear Solid V: The Phantom Pain are Kojima productions, so it makes a certain weird sense that Lisa is making a cameo. That doesn't necessarily mean there will be more overlap between the two games, although, with Kojima, one can never be certain.
Both Silent Hills and Metal Gear Solid V: The Phantom Pain are due out in 2015.