Chipmunk Leader(Thorntail the Mighty)

Keen Smell. The chickmunk has advantage on Wisdom (Perception) checks that rely on smell.

Multiattack. The chickmunk makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) piercing damage.

Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) slashing damage.

Leadership. Friendly chickmunk allies within 30 feet of the leader gain a +1 bonus to attack rolls and saving throws.

Fury Roar (Recharge 5-6). The chickmunk leader emits a powerful roar. All creatures of the chickmunk's choice within 10 feet of it must succeed on a DC 12 Wisdom saving throw or become 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.

This Chickmunk Leader is designed to be a formidable foe, providing both strong melee attacks and a leadership aura that boosts its allies. Adjust the stats as needed for the difficulty you're aiming for in your campaign.