Caliroa cerasi (Cherry slug sawfly)

The pear slug or cherry slug is the larva of the sawfly, Caliroa cerasi, a nearly worldwide pest. They are not slugs but are a kind of sawfly of the family Tenthredinidae. The pear slug is an important pest that eats leaves of cherry, pear, and plum trees, leaving behind a skeleton of veins. The larvae cover themselves in green slime, making themselves unpalatable to predators. When the larvae are fully grown, they drop off the…

— Wikipedia