Blight Mound is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Attacking Pests you control get +1/+0 and have menace. Whenever a nontoken creature you control dies, create a 1/1 black and green Pest creature token with "When this token dies, you gain 1 life."

Complete guide

Blight Mound is a powerful enchantment that ensures your fallen soldiers fuel a relentless swarm of Pests. Not only does it provide a steady stream of tokens, but it also transforms those tokens into evasive threats that are difficult for your opponents to block.

A Growing Swarm

Blight Mound has two main functions: a passive boost for Pests and a triggered ability that triggers whenever a nontoken creature you control dies. The passive ability gives all attacking Pests you control +1/+0 and menace. The second ability ensures that every time one of your nontoken creatures is put into the graveyard from the battlefield, you create a 1/1 black and green Pest token. These tokens come with their own triggered ability that grants you 1 life when they eventually perish.

Resolving the Trigger

When a nontoken creature you control dies, the triggered ability goes on the stack. Once it resolves, you create a Pest token. Note that the Pest token's life-gain ability is separate from the enchantment; the token itself has the text 'When this creature dies, you gain 1 life.' If Blight Mound leaves the battlefield, any Pests already created will still grant you life when they die, though they will lose the +1/+0 and menace bonuses while attacking.

Common Pitfalls

A common mistake is forgetting that the menace and power bonus only apply while the Pests are attacking. If a Pest is blocking or simply sitting on the battlefield, it is a 1/1 without menace. Additionally, remember that Blight Mound only triggers off nontoken creatures. If a Pest token dies, it will not trigger Blight Mound to create a new token, though you will still gain 1 life from the token's own ability.

When to Play Blight Mound

This enchantment is best suited for decks that utilize sacrifice outlets or expect to lose creatures in combat. It provides excellent board wipe protection; if an opponent destroys all creatures, you will create a new Pest for every nontoken creature you lost, effectively replacing your army with evasive tokens that can heal you later.

Interaction examples

The Shapeshifter Connection

Black Market Connections

If you use Black Market Connections to create a 3/2 Shapeshifter token, it has the Pest creature type because of changeling. While attacking, this token receives +1/+0 and menace from Blight Mound. However, because it is a token, if the Shapeshifter dies, it will NOT trigger Blight Mound to create a 1/1 Pest.

Managing Life Totals

Phyrexian Arena

Phyrexian Arena causes you to lose 1 life each turn to draw cards. By playing nontoken creatures and letting them die to create Pests, you can use the Pests as blockers. When the Pests die, their internal ability triggers, gaining you 1 life and effectively offsetting the life loss from the Arena.

Token Generation Cycle

Pest

If a nontoken creature dies while Blight Mound is out, you create a Pest token. If that Pest token then attacks, it becomes a 2/1 with menace. If it is blocked and dies, you gain 1 life. The cycle stops there, as the Pest is a token and won't trigger the Mound again.

Guide written with AI from the official text and rulings. Official English text prevails.