Fetid HorrorHow it works & interactions with other cards

Understanding the Pump Ability

Fetid Horror possesses an activated ability that costs one black mana. Unlike triggered abilities that happen automatically, you must choose to pay the cost to activate this effect. Each time you pay the black mana, a new instance of the '+1/+1 until end of turn' effect goes on the stack. There is no limit to how many times you can activate this ability in a single turn, provided you have the mana to pay for it.

Step-by-Step Resolution

When you activate the ability, it is put on the stack. Both players have a chance to respond before it resolves. Once the ability resolves, Fetid Horror gets +1/+1. If you activate it multiple times, each one resolves individually. Because this is an activated ability and not a triggered ability, it does not interact with effects that look for 'whenever' or 'when' something happens.

Common Mistakes

A frequent error is assuming that the +1/+1 bonuses are permanent counters. They are temporary stat increases that wear off during the cleanup step at the end of the turn. Additionally, players sometimes confuse activated abilities with triggered abilities; since Fetid Horror's ability starts with a cost followed by a colon, it is activated and will not be affected by cards that specifically double triggered abilities.

When to Activate

The best time to use Fetid Horror's ability is usually after your opponent has declared blockers. If they don't block it, you can spend all your available black mana to deal maximum damage. If they do block, you only need to spend enough mana to ensure Fetid Horror survives the combat or to trade with their creature.

Interaction examples

Mana Acceleration for Buffing

Solemn Simulacrum

You play Solemn Simulacrum and use its 'enters' ability to search for a basic Swamp and put it onto the battlefield. On your next turn, that extra Swamp provides an additional activation for Fetid Horror. If Solemn Simulacrum later dies and you draw a card that happens to be another Swamp, you increase the potential power ceiling of your Fetid Horror even further.

Interaction with Roaming Throne

Roaming Throne

If you have Roaming Throne on the battlefield with 'Horror' or 'Shade' chosen, you might expect it to double Fetid Horror's growth. However, Roaming Throne specifically states it affects 'triggered' abilities. Since Fetid Horror uses an 'activated' ability (indicated by the colon in '{B}:'), Roaming Throne does not cause the +1/+1 effect to happen an additional time. You still only get +1/+1 per black mana spent.

Individual Power Scaling

If Fetid Horror is attacking and you have three Swamps available, you can activate the ability three times. Each activation goes on the stack separately. If the opponent has no response, all three resolve, and Fetid Horror becomes a 6/9 creature (assuming its base is 3/6) until the end of the turn.