Cheapest priced copy (Dominaria United): $0.35 at Card Kingdom, near mint, their price list as of .
Monstrous War-Leech 
Creature — Leech Horror · */* · Uncommon · Dominaria United · #98
Kicker {U} (You may pay an additional {U} as you cast this spell.)
As this creature enters, if it was kicked, mill four cards. (To mill a card, put the top card of your library into your graveyard.)
Monstrous War-Leech's power and toughness are each equal to the greatest mana value among cards in your graveyard.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Dominaria United | 98 | Uncommon | $0.35 | $0.49 |
9 rulings from Wizards of the Coast
- 9 September 2022Monstrous War-Leech's second ability is a replacement effect, not a triggered ability. It happens at the same time that Monstrous War-Leech enters the battlefield, it doesn't use the stack, and it can't be responded to.
- 9 September 2022If a card in a graveyard has an {X} in its mana cost, X is 0.
- 9 September 2022If Monstrous War-Leech was kicked, it enters the battlefield with power and toughness each equal to the highest mana value among cards in your graveyard, including cards that were milled due to its replacement effect. For example, if you have no cards in your graveyard as it enters and you mill three land cards and a card with mana value 4, Monstrous War-Leech is a 4/4 creature entering the battlefield.
- 8 November 2024If you put a permanent with a kicker ability onto the battlefield without casting it, you can't kick it.
- 8 November 2024If a spell's kicker cost was paid, the spell is "kicked."
- 8 November 2024If a card or token enters as a copy of a permanent, the new permanent isn't kicked, even if the original was.
- 8 November 2024To determine a spell's total cost, start with the mana cost (or an alternative cost if another card's effect allows you to pay one instead), add any cost increases (such as kicker), then apply any cost reductions. The spell's mana value remains unchanged, no matter what the total cost to cast it was.
- 8 November 2024The kicker ability doesn't let you pay a kicker cost more than once.
- 8 November 2024If you copy a kicked spell on the stack, the copy is also kicked. If the copied spell is a permanent spell, the token the copy of that spell becomes when it enters is also kicked.