Mental Misstep
Instant
( can be paid with either 
or 2 life.)
Counter target spell with mana value 1.
Illustrated by
The Zeta Set#143UncommonEnglishLegality
Rulings
A card with Phyrexian mana symbols in its mana cost is each color that appears in that mana cost, regardless of how that cost may have been paid.
To calculate the converted mana cost of a card with Phyrexian mana symbols in its cost, count each Phyrexian mana symbol as 1.
As you cast a spell or activate an activated ability with one or more Phyrexian mana symbols in its cost, you choose how to pay for each Phyrexian mana symbol at the same time you would choose modes or choose a value for X.
If you’re at 1 life or less, you can’t pay 2 life.
Phyrexian mana is not a new color. Players can’t add Phyrexian mana to their mana pools.
If a spell has 
in its mana cost, X is considered to be the value chosen for it while that spell is on the stack.
Each Phyrexian mana symbol in a spell’s mana cost contributes 1 to that spell’s converted mana cost. For example, Mental Misstep’s converted mana cost is 1, regardless of how its cost was paid.