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 used her Bag of Tricks to create a Giant Boar.
When the Giant Boar attacks the Ghost with its Tusk, 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 magic item", as the creature is just created by a magic item, but it certainly seems to be a magical sort of creature.