Is it permissible to use a cup with a drawing on it of the unicorns mentioned in the Bible, knowing that the drawing is featureless?

If what makes life possible is removed from the image—such as the head, chest, or abdomen—then it is not forbidden, and its use is permissible. If the horse pictured on the cup is like that, then there is no harm in using it. Otherwise, a part of the image must be effaced to remove its prohibition.