Tressym

Within 60 feet of the tressym, magical invisibility fails to conceal anything from the tressym's sight.

The tressym has advantage on Wisdom (Perception) checks that rely on smell.

The tressym can detect whether a substance is poisonous by taste, touch, or smell.

With the DM's permission, a person who casts the find familiar spell can choose to conjure a tressym instead of a normal cat.

Melee Weapon Attack: +0 to hit, reach 5 ft., one target. Hit: 1 slashing damage.