This is is a 3.5" long specimen of Zlichovaspis rugosa from Atchana, Morocco. It has been prepared with nearly all of the surrounding limestone removed so that it appears to fly above the rock. Preparing a trilobite like this is a very time consuming process which requires a tremendous amount of skill.
Trilobites were a very diverse group of extinct marine arthropods. They first appeared in the fossil record in the Early Cambrian (521 million years ago) and went extinct during the Permian mass extinction (250 million years ago). They were one of the most successful of the early animals on our planet with over 25k described species, filling nearly every evolutionary niche. Due in large part to a hard exoskeleton (shell), they left a excellent fossil record.