Final answer:
Rushdie compares "commonwealth literature" to the mythical beast the Chimera, which symbolizes the diverse and composite nature of literature from different cultures of former British colonies.
Step-by-step explanation:
The mythical beast that Rushdie compares "commonwealth literature" to is the Chimera. This creature from Greek mythology is typically depicted as having parts from various animals, often a lion, a goat, and a serpent, representing something composed of very different parts.
In the given context, Rushdie might be referring to the diverse nature of "commonwealth literature," encompassing various cultures, styles, and voices from the former British colonies. This diversity defies simple categorization, much like a Chimera which is not a single creature but a composite one. A Chimera serves as a perfect emblem for this blend of literary traditions.