|Japanese (base text)||
Equip Cards constantly target the monster they are equipped to; even while negated, Equip Cards remain equipped and continue to target the monster. If the equipped monster is no longer face-up on the field, or is no longer a valid target, the Equip Card is immediately destroyed. This destruction is not treated as destruction by a card effect.
Equip Cards can be equipped to monsters controlled by either player, and changing control of a monster does not cause control of an Equip Card to change. While the equipped monster can be the opponent's, the Equip Card's controller is the one referred to as "you" in the Equip Card's card text, not the controller of the equipped monster.
Treating cards as Equip Cards
If a Monster Card is equipped to another monster, it is treated as an Equip Card and moved to a Spell & Trap Card Zone. While treated as such, it cannot be destroyed by card effects that destroy monsters, but can be destroyed by effects that destroy Spell/Trap Cards (without specifying Spell or Trap Card, meaning that they cannot be destroyed by "De-Spell" for example). If a monster that is treated as an Equip Card is sent to the Graveyard, it is not treated as being sent to the Graveyard as a monster, but becomes a monster again when it is in the Graveyard.
A monster treated as an Equip Card cannot have its equip target changed by other card effects, except Union Monsters equipped by their own effects. Union monsters are the only group of monsters that consistently, through the wording of their effects, treat themselves as Equip Spell Cards while equipped.
Equipped cards are still on the field, so effects or conditions that rely on a card "being sent from the field to the Graveyard", such as "Felgrand Dragon", still apply. (This is because they activate in the Graveyard, where they are monsters now, and not on the field.) Despite this, unless stated otherwise, Monster Cards cannot activate or apply their effects while treated as Equip Cards, as they are not monsters.
Pendulum Scale & Effect
Pendulum Scales are only applied if a Pendulum Monster card is in the leftmost/rightmost Spell & Trap Zone by being placed as a Pendulum Scale in the Pendulum Zone. Treating them as an Equip Card and placing them in these zones will not apply their Pendulum Scale and Pendulum Effects, and the Zone would not be treated as a Pendulum Zone.
A Link Monster's Link Arrows are only active if it is used as a Monster Card. If it is used as an Equip Card and placed in any Spell/Trap Zone, then its Link Arrows are not applied, and do not point to any zone or card.
If a Trap Card is equipped to a monster, it is treated as both an Equip Card and a Trap Card. For example, an equipped "Blast with Chain" can be destroyed by "Remove Trap" (since it is a Trap Card) and by "Gearfried the Iron Knight" (since it is an Equip Card), but not by "De-Spell" (since it is not a Spell Card). This type of Trap may be thought of as an "Equip Trap Card", but this is not an official term.