Cunning Nightbonder — ruling 1

Spells with flash that you control but didn't cast (perhaps because they're copies of a spell or because you took control of them from another player) can be countered.

Cunning Nightbonder — ruling 2

Players can't attempt to remove Cunning Nightbonder to raise the cost of a spell you wish to cast, but they can remove it to allow their spells and abilities to counter your spells.

Cunning Nightbonder — ruling 3

Cunning Nightbonder's last ability doesn't apply to itself while it's a spell.

Cunning Nightbonder — ruling 4

To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases, then apply any cost reductions (such as that of Cunning Nightbonder). The mana value of the spell remains unchanged, no matter what the total cost to cast it was.

Cunning Nightbonder — ruling 5

Cunning Nightbonder's cost reduction applies only to generic mana in a spell's cost. It can't reduce a spell's colored mana requirements. For example, your first Cunning Nightbonder won't normally reduce the cost of your second since it has no generic mana in its cost.

Cunning Nightbonder — ruling 6

A spell or ability that counters spells can still target spells with flash you cast. When that spell or ability resolves, your spell won't be countered, but any additional effects of the countering spell or ability will still happen.

Cunning Nightbonder — ruling 7

If Cunning Nightbonder enters the battlefield while a spell with flash that you cast is on the stack, that spell can't be countered, even though you don't get the {1} discount.

Cunning Nightbonder : règles, fonctionnement et interactions (MTG)

Cunning Nightbonder 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

Flash Spells with flash you cast cost less to cast and can't be countered.

How it works : Cunning Nightbonder

Original English text — Wizards of the Coast / Scryfall

#1April 17, 2020· Wizards of the Coast
Spells with flash that you control but didn't cast (perhaps because they're copies of a spell or because you took control of them from another player) can be countered.
No other card is named in this ruling.
#2April 17, 2020· Wizards of the Coast
Players can't attempt to remove Cunning Nightbonder to raise the cost of a spell you wish to cast, but they can remove it to allow their spells and abilities to counter your spells.
No other card is named in this ruling.
#3April 17, 2020· Wizards of the Coast
Cunning Nightbonder's last ability doesn't apply to itself while it's a spell.
No other card is named in this ruling.
#4April 17, 2020· Wizards of the Coast
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases, then apply any cost reductions (such as that of Cunning Nightbonder). The mana value of the spell remains unchanged, no matter what the total cost to cast it was.
No other card is named in this ruling.
#5April 17, 2020· Wizards of the Coast
Cunning Nightbonder's cost reduction applies only to generic mana in a spell's cost. It can't reduce a spell's colored mana requirements. For example, your first Cunning Nightbonder won't normally reduce the cost of your second since it has no generic mana in its cost.
No other card is named in this ruling.
#6April 17, 2020· Wizards of the Coast
A spell or ability that counters spells can still target spells with flash you cast. When that spell or ability resolves, your spell won't be countered, but any additional effects of the countering spell or ability will still happen.
No other card is named in this ruling.
#7April 17, 2020· Wizards of the Coast
If Cunning Nightbonder enters the battlefield while a spell with flash that you cast is on the stack, that spell can't be countered, even though you don't get the discount.
No other card is named in this ruling.