Overblaze

Instant — Arcane • Mana cost: {3}{R} • Betrayers of Kamigawa • Uncommon

Each time target permanent would deal damage to a permanent or player this turn, it deals double that damage to that permanent or player instead.
Splice onto Arcane {2}{R}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Illustrated by Ron Spencer.