Narrative Shapeshifting

An Intellectual Animal in a cartoon just saw something strange land in the cornfields. It is something beyond description. The animal wants to tell his owners about the dangerous thing he just saw, unfortunately, he can't talk. So how does he convey what he saw? He alters his physical appearance to resemble the strange thing he just saw.

It's a form of Voluntary Shapeshifting in which one character changes his appearance to tell a story or warn of a danger, especially if that character cannot speak or has trouble speaking. It could be especially jarring if the character shows no signs of being able to shapeshift in any other time.

The character does not have to be The Speechless in order to invoke this trope, and may indeed combine shapeshifting with spoken dialogue to get the idea of the story he is telling across.

A minor variation is when a speechless character attempts to warn the others of the impending danger by playing a nice game of charades.

Anime and Manga

 * Pokémon: Ash's Pikachu has done this on occasion.
 * The opening credits of My Neighbor Totoro.

Film

 * In Enchanted, the chipmunk can't speak outside the fairy tale world, so he tries using charades to warn Prince Edward that Nathaniel is planning to poison Giselle with an apple. It doesn't work; Edward just thinks the chipmunk is praising his greatness.

Video Games

 * Mario in Super Mario RPG uses this to get around his Heroic Mime status.
 * In The Legend of Zelda: Oracle of Ages, this appears to be the case when Link is telling the Funny Joke to the depressed boy, as Link's body contorts in ways never before seen from our favorite Heroic Mime.
 * In Twilight Princess, after the first segment in Hyrule Castle, Midna briefly shapeshifts into screaming images of Ilia and Colin to get Link to help her. A bit of Big Lipped Alligator Moment since she could easily have made the point without doing it and never displays this ability at any other point in the game.

Western Animation

 * Courage the Cowardly Dog: Courage would often do this to warn Eustace and Muriel of the Monster of the Week.
 * A Pup Named Scooby-Doo: Scooby would also do this to tell the others about the monster.
 * The other incarnations of Scooby Doo may have done this to some degree, but not as much.
 * In the Tom and Jerry cartoon "Of Feline Bondage", Jerry uses this trope to tell his fairy godmother about his cat troubles.
 * A "Simpsons" short on The Tracey Ullman Show had Maggie briefly turn into Bart in order to convey the idea "Bart stole the cookies."
 * Doom Kitty in Ruby Gloom uses her extremely thin, flexible and strong tail to make shapes ? not strictly shapeshifting, but it does alter her appearance after a fashion. Of course, only Ruby can understand her.
 * Abu and Iago do this in Aladdin.
 * The Genie is likely to have done this as well.
 * In the South Park episode "Up the Down Steriod", Timmy attempts to tell Mr. Mackey about Jimmy using steriods, but doesn't have much luck since all he can say is "Timmy" and "Jimmy". So he mimics Jimmy shooting up and then getting all muscular, but Mr. Mackey still doesn't get it.
 * Baby Beaker in Muppet Babies, explaining his fear of the monster under his bed to the other babies (since, like Adult Beaker, all he can say is "Meep!").