WoW:MACRO mountspecial

/mountspecial is a slash command causing your mount or druid Flight Form to perform a special stunt, depending on the mount. For ground mounts, this animation can be triggered while standing and pressing the space bar, but for flying mounts, only the slash command can be used. As of Patch 2.2, this function cannot be used anymore while moving (excluding taxi mounts, which still use their 'hovering' animation then).

List of stunts per mount type

• Horses, Rams, Elekks, Mechanostriders, and Talbuks: rear up
• Sabers: roar
• Kodos and Wolves: throw the head from side to side with a roar
• Wyvern: roar
• Nether Drake: rear up
• Flight Forms: perform a loop

Note: though some animations imply the mount makes a noise - for example, "roars" - only a few make a noise.