For those who aren't sure exactly which character is which, I've compiled an answer key. The title in parentheses is what they're from, for the more obscure ones.
-Batman
-The Doctor (Doctor Who)
-Harry Potter and Hedwig
-Sonic the Hedgehog
-Cameron Poe (Con Air)
-Vriska Serket (Homestuck)
-Andrew Hussie (Homestuck)
-Ronald McDonald
-The Burger King
-Nyan Cat
-Mario
-Steve Urkel (Family Matters)
-Optimus Prime (Transformers)
-Navi (The Legend of Zelda: Ocarina of Time)
-Jigglypuff (Pokemon)
-King Dedede (Kirby)
-Ice King (Adventure Time)
-Cloud and Sephiroth (Final Fantasy 7)
-Marty McFly (Back to the Future)
-Garfield
-Zeddie Little (Ridiculously Photogenic Guy)
-Shaggy and Scooby-Doo
-Elmer Fudd and Bugs Bunny (Looney Tunes)
-Tarzan