Lighten the Load (Red)

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When this attacks, you may discard a card or destroy an item you control. If you do, this gets go again.

Rulings

From the Compendium of Rathe release notes

Lighten the Load triggers when it resolves on the stack and becomes an attacking card on the combat chain. This is an optional effect: you choose whether or not to discard a card or destroy an item you control or do nothing when this triggered effect resolves. If you choose and discard a card, or choose an destroy an item you control this way, Lighten the Load will get go again.
When resolving Lighten the Load’s triggered effect, there is no priority in between any of the effects generated (e.g. discarding a card, destroying an item, 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)