Aethersling (Red)

Deal 4 arcane damage to any target.

If this deals damage, you may

your hero. If you do, this gets go again.

Rulings

From the Omens of the Third Age release notes

When playing Aethersling, you must declare a target. When Aethersling resolves, you will deal 4 arcane damage to that target. Then, if Aethersling deals damage, you may choose to your hero. If you choose to your hero this way, Aethersling gets go again.
When resolving Aethersling, there is no priority between any of the effects generated (e.g. dealing arcane damage, tapping your hero, this getting go again).

Keyword notes

Go again - Go again allows multiple actions to be played in a turn when usually playing an action with use up your action point, and therefore end your turn. A card with go again gives the controller of that card or activated ability 1 action point when it resolves.

When an action with go again resolves, its controller gains 1 action point.
Multiple instances of go again on the same card or activated ability do not stack. If a card or activated ability has multiple instances of go again when it resolves its controller gains 1 action point only.
If an action with go again does not resolve, its controller does not gain 1 action point.
You cannot reveal a card with no to Belittle. The card must have a value to its power that is 3 or less. (0 is a value)