natural shape: a shape created by natural forces; not man-made
entity: that which is perceived or known or inferred to have its own distinct existence (living or nonliving)
ixodes scapularis: parasitic on mice of genus Peromyscus and bites humans; principal vector for Lyme disease in eastern United States (especially New England); northern form was for a time known as Ixodes dammini (deer tick)