In our last session, the party was fighting a Ghost. A ghost has, among other characteristics, damage resistance to "Bludgeoning, Piercing, and Slashing from Nonmagical Attacks". The Druid had previously cast Conjure Animals to create eight Owls.
When the Owl attacks the Ghost with its Talons, does that count as a "magical attack" and thereby that the Ghost's damage resistance won't apply?
The standard reference that I've found for figuring out if an attack is magical is in the Sage Advice Compendium, which has this to say under "Is the breath weapon of a dragon magical?":
Determining whether a game feature is magical is straightforward. Ask yourself these questions about the feature:
- Is it a magic item?
- Is it a spell? Or does it let you create the eﬀects of a spell that’s mentioned in its description?
- Is it a spell attack?
- Is it fueled by the use of spell slots?
- Does its description say it’s magical?
If your answer to any of those questions is yes, the feature is magical.
I'm not sure, though, if this qualifies as "is it a spell" or "is it a spell attack", as it isn't quite either, but being a summoned fey creature in the form of a beast sure seems like a magical sort of thing more so than, say, a dragon's breath weapon would be.