Summary Judgment

Instant

Summary Judgment deals 3 damage to target tapped creature.
Addendum — If you cast this spell during your main phase, it deals 5 damage instead.

Any challenge to Azorius authority is met with swift and potent retribution.

Related card: Slayer's Bounty

2024-01-12 Addendum abilities of instant spells apply while the spell is resolving, not immediately after casting it. If the spell is countered, you don't get the addendum bonus.
2024-01-12 If an effect copies a spell with an addendum ability while it's on the stack, the copy wasn't cast at all, so you won't get the addendum bonus.

Card is in preconstructed decks:

mtg.wtf