There are several special kinds of metaphors such as personal metaphor, animal metaphor and allegory.
Personification is the name given to a special kind of metaphor in which abstract ideas or inanimate objects (the tenor) are identified with persons (the vehicle), i. e. are ascribed human characteristics or actions.
There are several degrees of personification. A thing or idea can be fully personified or a thing or idea can be partially personified, and partially retain its own characteristics.
In this anti-war poem the grass is endowed with speech (the classical rhetorics called it prosopopoeia) and at the same time remains what it is.
Sometimes personification assumes the form of apostrophe, that is, of a direct address to things or abstract notions thus endowing them with consciousness.
The formal indications of personification may be (i) capitalizing and (ii) the substitution of personified names by the personal pronouns he or she (and, accordingly, the use of the possessive his or her)
Personification serves various aims in artistic texts. In the classicist poetry of the 17-18th centuries it was used merely as a mythological and rhetorical tradition. In later writings it was used to add dramatic power to the description, to express the author's individual vision of the world.
Animalification is the name given to a special kind of metaphor in which abstract ideas of inanimate objects (the tenor; are identified with beasts (the vehicle), i. e. are ascribed animal characteristics or actions.
Animal metaphors are generally based on verbs and adjectives. Verbs of animal movements and of animal voices are for instance collocated with non-animal nouns.
The allegory is a complete literary work of symbolic nature that can be treated as an elaborate and continuous metaphor. The reader is expected to see the resemblance between the facts of the story (the vehicle) and the ideas that are implied (the tenor). A well-known instance of allegory is fables, in which birds and beasts are made to think, speak and act like men.
A good illustration of allegory is Walt Whitman's 0 Captain! My Captain!, a poem, in which the great American poet mourns the death of Abraham Lincoln, president of the USA from 1861 to 1865, who held office during the Civil War between the Northern and Southern States. The North defeated the South, slavery was abolished but the victory was marred by the assassination of Lincoln. In the poem the North is identified with a ship, and President Lincoln, with its captain.