Echolocation. The shrew can't use its blindsight while deafened. While deafened, it has disadvantage on attack rolls, and attack rolls against it have advantage.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 4 (1d4 + 2) piercing damage.

Ferocious Bite. When the shrew hits a target with its bite attack, it will attack that same target the with a second bite attack. This second bite attack has advantage. If the second bite attack hits, the target must succeed on a DC 12 Wisdom saving throw or be frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.