Curse of Inertia — ruling 1

A Curse spell targets the player it will enchant like any other Aura spell, and a Curse stays on the battlefield like any other Aura. If the enchanted player gains protection from the Curse’s color (or any other characteristic the Curse has), the Curse will be put into its owner’s graveyard.

Curse of Inertia — ruling 2

Each of the Curses can be attached to any player, including the player who cast the Curse.

Curse of Inertia — ruling 3

Curse is an enchantment type, not a creature type (or any other kind of subtype).

Curse of Inertia — ruling 4

The ability won’t trigger when a creature attacks a planeswalker controlled by the enchanted player.

Curse of Inertia — ruling 5

The Curse subtype has no inherent rules meaning, but two cards in the Innistrad set (Bitterheart Witch and Witchbane Orb) refer to Curses.

Curse of Inertia — ruling 6

Curse of Inertia’s ability will trigger only once per attacking player per combat phase, no matter how many creatures that player attacks with.

Curse of Inertia — ruling 7

Even though the attacking player chooses the target of the ability, the ability is still controlled by the player who controls Curse of Inertia. Notably, a creature with hexproof controlled by the player who controls Curse of Inertia could be chosen, even though another player may be choosing the target.

Curse of Inertia : règles, fonctionnement et interactions (MTG)

Curse of Inertia 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

Enchant player Whenever a player attacks enchanted player with one or more creatures, that attacking player may tap or untap target permanent of their choice.

How it works : Curse of Inertia

Original English text — Wizards of the Coast / Scryfall

#1October 17, 2013· Wizards of the Coast
A Curse spell targets the player it will enchant like any other Aura spell, and a Curse stays on the battlefield like any other Aura. If the enchanted player gains protection from the Curse’s color (or any other characteristic the Curse has), the Curse will be put into its owner’s graveyard.
No other card is named in this ruling.
#2October 17, 2013· Wizards of the Coast
Each of the Curses can be attached to any player, including the player who cast the Curse.
No other card is named in this ruling.
#3October 17, 2013· Wizards of the Coast
Curse is an enchantment type, not a creature type (or any other kind of subtype).
No other card is named in this ruling.
#4October 17, 2013· Wizards of the Coast
The ability won’t trigger when a creature attacks a planeswalker controlled by the enchanted player.
No other card is named in this ruling.
#5October 17, 2013· Wizards of the Coast
The Curse subtype has no inherent rules meaning, but two cards in the Innistrad set (Bitterheart Witch and Witchbane Orb) refer to Curses.
No other card is named in this ruling.
#6October 17, 2013· Wizards of the Coast
Curse of Inertia’s ability will trigger only once per attacking player per combat phase, no matter how many creatures that player attacks with.
No other card is named in this ruling.
#7October 17, 2013· Wizards of the Coast
Even though the attacking player chooses the target of the ability, the ability is still controlled by the player who controls Curse of Inertia. Notably, a creature with hexproof controlled by the player who controls Curse of Inertia could be chosen, even though another player may be choosing the target.
No other card is named in this ruling.