Monastery Swiftspear

Creature — Human Monk

Haste Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

First printed September 26, 2014 in Khans of Tarkir

Legality

March 19, 2021
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.
September 20, 2014
Prowess goes on the stack on top of the spell that caused it to trigger. It will resolve before that spell.
September 20, 2014
Once it triggers, prowess isn't connected to the spell that caused it to trigger. If that spell is countered, prowess will still resolve.
September 20, 2014
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.