Printings
Khalni Hydra
Card Information
Type: Creature — Hydra
Mana Cost: 
CMC: 8
Part of the Reserved List: No
Color Identity:
Set: Rise of the Eldrazi (ROE)
Rarity: Mythic
Collector Number: 192
Oracle Text
This spell costs {G} less to cast for each green creature you control. Trample
Keywords
Format Legalities
Card Rulings
- June 15, 2010
If an effect (such as the one from Lodestone Golem) imposes an additional generic mana cost to casting Khalni Hydra, the Hydra's ability will reduce it too. It'll reduce the amount of green mana you need to spend first, though.
Source: wotc - June 15, 2010
For the purpose of determining the cost reduction, the number of green creatures you control is checked as you cast Khalni Hydra, before your last chance to activate mana abilities to pay for it. For example, if you control Wild Cantor (a red and green creature with the ability "Sacrifice Wild Cantor: Add one mana of any color.") as you cast Khalni Hydra, first the cost to cast Khalni Hydra is reduced by {G}, then you could sacrifice Wild Cantor for mana to help pay for it.
Source: wotc - June 15, 2010
Khalni Hydra's cost reduction effect doesn't change its mana cost or mana value.
Source: wotc
Price History
To study a single card is to glimpse the heart of a spell - a frozen moment of ambition, artistry, and arcane intent. Within each glyph lies a spark: a story untold, a duel turned, a destiny altered. Treat it not as mere parchment, dear seeker, but as a shard of the Multiverse itself.