Revelsong HornHow it works & interactions with other cards

What it Does

Revelsong Horn is an activated ability artifact that grants a target creature +1/+1 until the end of the turn. To activate this, you must pay one generic mana, tap the Horn itself, and tap one untapped creature you control. This cost is unique because it allows you to utilize creatures that may have summoning sickness or those you wish to keep out of direct combat to still influence the power and toughness of your attackers or blockers.

Step-by-Step Resolution

First, announce you are activating the ability of Revelsong Horn and choose a target creature to receive the bonus. Second, pay the costs: spend one mana, tap Revelsong Horn, and choose an untapped creature you control to tap. Once the ability is placed on the stack, players may respond. When the ability resolves, the target creature receives its +1/+1 buff. If the target becomes illegal before resolution, the entire ability fails to resolve and no creature is tapped as a result of the resolution—though the costs remain paid.

Common Mistakes

A common mistake is forgetting that 'Tap an untapped creature you control' is part of the cost, not the effect. You must have a creature available to tap at the moment you activate the ability. Additionally, note that tapping a creature to pay for the Horn's ability does not trigger 'attacks' abilities, as the creature is being tapped for a cost rather than being declared as an attacker during the declare attackers step.

When to Play It

The Horn is most effective during the declare attackers or declare blockers steps. Because it requires a target, you can wait to see how your opponent blocks before deciding which creature needs the extra boost to survive combat or deal lethal damage. It is also a great way to use mana generated by artifacts like Sol Ring or Arcane Signet if you have no other spells to cast during your turn.

Interaction examples

Powering Up with Sol Ring

Sol Ring

You tap Sol Ring to add two colorless mana to your mana pool. You use one of those mana to pay for Revelsong Horn's activation cost, tap the Horn, and tap an untapped creature you control. This allows you to boost an attacking creature's stats while still having one mana left over from your Sol Ring for other effects.

Fixing Math with Arcane Signet

Arcane Signet

During your combat phase, you realize your attacker is one power short of destroying a blocker. You tap Arcane Signet for mana, use it to activate Revelsong Horn, and tap a utility creature that just entered the battlefield. Even though the utility creature has summoning sickness, it can still be tapped to pay the Horn's cost, giving your attacker the +1/+1 needed to win the trade.