OCG Rulings Sending an Equip Spell Card from the Field to the Graveyard is a cost to activate the

effect of "Guardian Eatos". This effect targets 1 to 3 monsters in the opponent's Graveyard.[2]

The effect of "Guardian Eatos" which increases its ATK resolves as part of the same resolution which banishes the targeted monsters.[2]

You may send to the Graveyard an Equip Spell Card that your opponent controls as an activation cost for the effect of "Guardian Eatos".[3]

If "Dimensional Fissure" is active, then you may still activate the effect of "Guardian Eatos" by sending to the Graveyard a Monster Card that is being treated as an Equip Spell Card, such as a Union Monster.[4]

The effect of "Guardian Eatos" which banishes monsters from your opponent's Graveyard and the effect which increases its ATK by 500x are considered to resolve simultaneously.[5]

Example: If "Guardian Eatos" banishes a monster(s), then the opponent can activate "Dimensional Inversion". She does not miss the timing.[5]