Betsy the Cow (Magical)

Charge. If Betsy moves at least 20 feet straight toward a target and then hits it with a gore attack on the same turn, the target takes an extra 7 (2d6) piercing damage.

Magical Milk. A creature can drink milk Betsy for 1 minute to gain enough milk for 1 use. A creature can drink the milk as a bonus action. If a creature that is not a fiend, undead, construct, or abberation drinks the milk, it regains 1d6 hit points. 

Innate Spellcasting. Betsy the Cow's innate spellcasting ability is Charisma (spell save DC 16, +6 to hit with spell attacks). She can innately cast the following spells, requiring no material components:

At will: bless, druidcraft

1/day each: chromatic orb, hellish rebuke (deals radiant damage instead of fire), guiding bolt

Gore. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d6+4) piercing damage.

Rainbow (1/day). A rainbow comes out of Betsy's mouth. Each creature in a 30 ft. cube must succeed on a Dexterity saving throw or take 13(4d6) radiant damage, or half as much on a succesful one.