If you have a Spell prepared that has the Ritual tag, you can cast that
Spell as a Ritual. This means it can be either casted as an using the spell's
Casting time (usually within the turn) and using the
Mana equal to the
Spell level, or alternatively when cast as a
Ritual Spell, it takes 10 minutes and uses no
Mana.
While Casting in this way, the creature gain the status effect of
Casting.