Transformootion

Caster and 10 other willing creatures assume the form of a Cow with the following bonus stats in addition to its own stats:

STR: +4, DEX: +0, CON: +2, INT: -4, WIS: +0, CHA: -3, HP: Current; AC: Current.

If INT is reduced to 0 or lower due to the spell, target creature does not transform.

You keep your personality, but otherwise acquire other Cow stats as shown in Monster Manual, and can speak to and understand other Cows.

Each creature may decide on appearance of Cow, but size is restricted to no more than six feet tall from ground to horns. 

Unwilling creatures must make a Wisdom saving throw of 15 to keep from being turned into a Cow. 

On failure, creature will turn into a Cow, but will not retain its own personality, and take the stats of a Cow rather than their own stats.

Verbal component:  In bovis corpore transmuto.

Spell ends when caster loses concentration (WIS save).