If Get Exited! has no valid target when it resolves (because the opponent killed their own unit with Hidden Blade in response), does the caster still have to discard a card?

Ruling: Yes, you still have to discard a card even if there is no valid target when Get Exited! resolves.

Sequence:

• Get Exited! is played targeting a unit
• Opponent responds with Hidden Blade, killing their own unit
• Chain resolves: Get Exited! has no valid target, but the caster still must discard a card