Hydra's GrowthHow it works & interactions with other cards

What It Does

Hydra's Growth is an Aura that attaches to a creature. When it first enters the battlefield, it grants a single +1/+1 counter to that creature. The real power, however, lies in its triggered ability: at the start of each of your upkeep steps, you count the number of +1/+1 counters currently on the enchanted creature and add that many more to it.

How It Resolves Step by Step

First, cast Hydra's Growth by targeting a creature. When the spell resolves and enters the battlefield, its first ability triggers, putting a +1/+1 counter on the creature. If the Aura is destroyed before this first trigger resolves, the creature still gets the counter. Then, during every one of your subsequent upkeep steps, the second ability triggers. You check the current number of +1/+1 counters (for example, 3), and you place that same amount (3 more) onto the creature, resulting in a total of 6.

Common Mistakes

A common misconception is how 'doubling' works with other effects. Mathematically, doubling is treated as placing new counters. If an effect says you cannot place counters on a creature, Hydra's Growth will fail to double them. Additionally, remember that this effect only doubles +1/+1 counters; it does not affect keyword counters like flying or lifelink, nor does it double the creature's base power and toughness.

When to Play It

This card is best played when you can protect the enchanted creature, as the investment grows more valuable over time. Because it triggers at the start of your upkeep, you want to cast it during your main phase to ensure it is ready to trigger the following turn. It pairs excellently with creatures that already have trample to ensure all that gathered power actually reaches your opponent.

Interaction examples

Exponential Growth and Trample

Garruk's Uprising

If you have Garruk's Uprising on the battlefield, your creatures have trample. You cast Hydra's Growth on a 2/2 creature. It enters, gets a +1/+1 counter, becoming a 3/3. On your next upkeep, Hydra's Growth doubles the counters, adding 1 more for a total of two +1/+1 counters. The creature is now a 4/4. Because its power is now 4 or greater, Garruk's Uprising allows you to draw a card, and the creature can now trample over blockers.

Maintaining Card Advantage

Sylvan Library

During your upkeep, Hydra's Growth triggers first to double your creature's counters. After that, you move to your draw step where Sylvan Library triggers. While these cards don't have a direct mechanical synergy in terms of counters, the massive creature created by Hydra's Growth puts immense pressure on the board, while Sylvan Library helps you dig for protection spells or hexproof effects to keep your growing threat alive.