when an actor portrays a mentally disabled character as *totally* mentally disabled, with few if no redeeming values. Oftentimes in Hollywood, actors are known to sink to the lowest common denominator, and try to play mentally disabled characters in what are really shameless attempts to win audience and critic sympathy, in what is usually a desperate bid for an Oscar. Sometimes, playing a mentally disabled character actually *does* result in winning an Academy Award, so long as you *don't* "go full retard":

That is, the mentally disabled character *should* face some obstacles, but also have some redeeming values (an "idiot savant"). For example, Dustin Hoffman in "Rain Man" was "mentally disabled" but he was really an autistic mathematical genius. Tom Hanks in "Forrest Gump" was mentally handicapped, but it still a very functional individual and in his own way, charming in his honest if simple morality to people me meets, and further, he has some real above-average talents, such as being an Olympic-level ping pong player and an excellent long-distance runner.

However, this doesn't work if the actor's performance as the mentally disabled character has *absolutely* no redeeming values and is indeed "full retard" mode: a character that is utterly handicapped mentally and really has no "hidden surprise talents"; this ends up just being a film following an average mentally disabled person around for the whole run time.

Such was infamously the case with Tugg Spee...