Unlike you, the Enemy does not need to collect Spell Cards. It has 3 Spells already at its disposal, 1 for each Hero. It will actually cast a Spell instead of taking a normal Research Action. The Enemy will gain the Victory Points shown and the Spell will take effect.
Spells cast by the Enemy can still be interrupted by player Spells. If a Spell is copied and turned against the Enemy, the player may make choices for the Enemy. Such as which Unit or Resources the Enemy loses.
This action will fail if the Enemy does not have the required Resources available to cast a Spell. If a Spell is useless (such as a Spell that affects the area around a Hero, but there are no player Units around to be affected), the Spell is still cast and the Enemy gains the Victory Points.
Note: When a Research Action is taken, the player can follow it as if it was a normal Research Action.