Biomancer's Familiar — ruling 1

Activated abilities contain a colon. They’re generally written “[Cost]: [Effect].” Some keyword abilities are activated abilities and will have colons in their reminder text. Triggered abilities (starting with “when,” “whenever,” or “at”) are unaffected by the cost reduction ability of Biomancer’s Familiar.

Biomancer's Familiar — ruling 2

Biomancer’s Familiar affects only abilities of creatures you control on the battlefield. The costs of activated abilities of creature cards that work in other zones (such as cycling) won’t be reduced.

Biomancer's Familiar — ruling 3

An ability that has only one generic mana and some amount of other mana symbols in its activation cost will have its cost reduced by {1}.

Biomancer's Familiar — ruling 4

The last ability of Biomancer’s Familiar doesn’t add or remove any counters. It just lets the creature adapt despite already having +1/+1 counters on it.

Biomancer's Familiar : règles, fonctionnement et interactions (MTG)

Biomancer's Familiar 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

Activated abilities of creatures you control cost less to activate. This effect can't reduce the mana in that cost to less than one mana. : The next time target creature adapts this turn, it adapts as though it had no +1/+1 counters on it.

Complete guide

Biomancer's Familiar is a versatile utility creature that provides a massive discount to your army's activated abilities. Not only does it make your creatures more efficient, but it also allows your creatures to exceed their natural limits by adapting multiple times. This Mutant is a cornerstone for any deck looking to maximize its mana efficiency on the battlefield.

Slashing Activation Costs

The primary role of Biomancer's Familiar is to reduce the mana cost of activated abilities by {2}. Remember that an activated ability is always written as [Cost]: [Effect]. This reduction applies only to creatures currently on the battlefield; it does not help with ability costs of creature cards in your hand or graveyard. Importantly, this effect cannot reduce the mana requirement of an ability to zero; you must always pay at least one mana if the ability has a mana cost associated with it.

Adapting Beyond Limits

Usually, a creature with the Adapt keyword cannot gain new counters if it already has +1/+1 counters on it. By tapping Biomancer's Familiar, you ignore this restriction for the next time a target creature adapts that turn. This doesn't remove existing counters; it simply lets the ability resolve successfully and add more +1/+1 counters as if the creature were 'fresh'.

Timing and Restrictions

The cost reduction is a static ability that is always active while the Familiar is on the battlefield. It only reduces generic mana costs. For example, if an ability costs {1}{G}, the Familiar will reduce the {1} but cannot touch the {G}, meaning the final cost is still {G}. Because the cost cannot go below one mana, an ability costing {2} becomes {1}, and an ability costing {1} remains {1}.

Interaction examples

Managing Mana Dorks

Llanowar Elves

If you control Llanowar Elves, its ability is {T}: Add {G}. Since this ability does not have a generic mana cost to reduce, Biomancer's Familiar provides no discount here. The cost remains simply tapping the creature.

Minimum Cost Threshold

Birds of Paradise

Similar to the Elves, Birds of Paradise has a cost of only {T}. Even if you had an ability that cost {2}, the Familiar would reduce it to {1}. If the Birds of Paradise gained an ability like '{2}: Untap this creature,' the Familiar would reduce that cost to {1}, but it could never make it {0}.

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

How it works : Biomancer's Familiar

Original English text — Wizards of the Coast / Scryfall

#1January 25, 2019· Wizards of the Coast
Activated abilities contain a colon. They’re generally written “[Cost]: [Effect].” Some keyword abilities are activated abilities and will have colons in their reminder text. Triggered abilities (starting with “when,” “whenever,” or “at”) are unaffected by the cost reduction ability of Biomancer’s Familiar.
No other card is named in this ruling.
#2January 25, 2019· Wizards of the Coast
Biomancer’s Familiar affects only abilities of creatures you control on the battlefield. The costs of activated abilities of creature cards that work in other zones (such as cycling) won’t be reduced.
No other card is named in this ruling.
#3January 25, 2019· Wizards of the Coast
An ability that has only one generic mana and some amount of other mana symbols in its activation cost will have its cost reduced by .
No other card is named in this ruling.
#4January 25, 2019· Wizards of the Coast
The last ability of Biomancer’s Familiar doesn’t add or remove any counters. It just lets the creature adapt despite already having +1/+1 counters on it.
No other card is named in this ruling.