Monastery Swiftspear
Creature — Human Monk
Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
She focused her mind on the volcano's fury, and hers erupted in kind.
Illustrated by
The Brothers' War#144UncommonEnglishLegality
Rulings
Any spell you cast that doesn't have the type creature will cause prowess to trigger. If a spell has multiple types, and one of those types is creature (such as an artifact creature), casting it won't cause prowess to trigger. Playing a land also won't cause prowess to trigger.
Prowess goes on the stack on top of the spell that caused it to trigger. It will resolve before that spell.
Once it triggers, prowess isn't connected to the spell that caused it to trigger. If that spell is countered, prowess will still resolve.
An ability that triggers when a player casts a spell resolves before the spell that caused it to trigger. It resolves even if that spell is countered.