Keen Smell. The deer has advantage on Wisdom (Perception) checks that rely on smell. Charge. If the deer moves at least 20 feet straight toward a target and then hits it with a ram attack on the same turn, the target takes an extra 2 (1d4) bludgeoning damage. If the target is a creature, it must succeed on a DC 10 Strength saving throw or be knocked prone.
Ram. Melee Weapon Attack: +2 to hit, reach 5 ft, one target. Hit: (1d4) bludgeoning damage.
Evasive. Unless it has taken the attack action on it's last turn, the Deer can dodge using it's bonus action.