A crocodile head overlaps 18-Rabbit's loin cloth, and can be identified by its set of upward-curving teeth splayed out on both sides. The crocodile muzzle points downward, and its front feet hang down from the king's waist.
"The Maya saw this crocodile head as the dark cleft in the Milky Way, and the tree as the Milky Way itself, arching across the sky from the southwest to the northeast. However, this stela was more than just a realization of the myth--it recorded the pattern of the sky after sunset on the night of December 5, 711. On this night, Venus made its first appearance as Eveningstar, becoming visible at sunset in the constellation of Sagittarius at the base of the Milky Way crocodile tree. Thus the stela replicates symbolically what Waxaklahun-Ubah-K'awil and his people saw on that important night."
Linda Schele & Peter Mathews, The Code of Kings: The Language of Seven Sacred Maya Temples and Tombs, p. 143