Auto-cast

Auto-cast is a toggle that allows a spell or ability to be used automatically. When auto-cast is active for an ability, it's signified by gold rotating around the edges of the ability's icon. Auto-cast can be activated or deactivated by right-clicking on an auto-castable ability.

In Warcraft III
In Warcraft III, auto-cast was seen on a variety of abilities, such as Repair, Heal, Web, and Abolish Magic.

If an ability in Warcraft III can be auto-cast, its icon will have a yellow bracket in each corner:



In World of Warcraft
In World of Warcraft, auto-cast is generally seen on abilities used by hunter pets, minions, and other summoned units. This includes abilities like Growl (pet), Deadly Bite, and Devour Magic.

If an ability in World of Warcraft can be auto-cast, its icon will have a small yellow triangle in each corner: