Does Nystul’s Magic Aura mask wording allow a Fey familiar masked to be a beast to enter an area under the effect of the Hallow spell? "You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type…"

The hallow treats the masked fey as if it were a beast. It can enter just fine. An extra effect bound to the hallow might still affect it, though.

— Dan Dillon 👥 (@Dan_Dillon_1) January 23, 2020

So same reasoning a caster who Nystuls themself to be an elemental wouldn’t be affected by the hold person spell? Spells and magical effects would indeed treat that caster as an elemental.

— Dan Dillon 👥 (@Dan_Dillon_1) January 25, 2020