Channeling

Channeling or channeled spells are Abilities that require the caster to stop acting for the duration of the spell. As such, the spell is ended when the channeling unit takes another action or is interrupted by a hostile spell. While the spell is being channeled, a draining bar will appear on the screen, indicating how much time is left in the channel.

Interrupting Channeled Abilities
If the channeling unit issues another command, such as moving, stopping, or attacking, the channeling will end. Using the active abilities of most items will also interrupt channeling, with the exception of Shadow Amulet and Shadow Blade.

Any disable that would normally prevent a unit from casting will also interrupt channeling. This includes Stuns, Mini-Stuns, Silence, Pauses, Cyclone, Hex, and Sleep. Though they do not prevent casting, Entangle and Ensnare effects will interrupt channeling. Certain abilities that forcibly move units, such as Dark Seer's Vacuum and Magnus' Skewer will interrupt channeling due to the short disable they provide. Tiny's Toss will also interrupt channeling, even when used on an ally. A notable exception is Force Staff, which will not interrupt channeling unless it is used by the channeling unit itself.

Some channeled abilities, such as Epicenter and Teleportation will not perform their effects until the end of the channel's duration. However, like all channeled spells, they will expend mana and go on cooldown as soon as they are cast. If the channel is interrupted, the mana and cooldown will be wasted, and the spell will have no effect. This is in contrast to other, non-channeled spells with high cast times, such as Assassinate and Requiem of Souls, which will not expend mana or go on cooldown until the spell has been completed. Certain channeled spells, such as Illuminate and Powershot will still perform their effect even if they are cancelled, usually at the cost of damage.