The cownicorn is like a Unicorn, but wheras a Unicorn is rather more goatish than it'd admit to, the Cownicorn is unabashedly bovine.
While both types will lay their heads in a virgin's lap, the Cownicorn will take the opportunity to chew cud.
A unicorn's horn cures ailments, purifies water and detects poison. So does a Cownicorn's, with the added benefit of keeping our milk fresh. As a side benefit Cownicorn milk is great in coffee.