Horned Spanworm Moth Caterpillar (Nematocampa resistaria) — Caterpillars are not always easy to identify …but we think we’ve got this one. This unusual caterpillar has eversible tentacles. When relaxed, the tentacles are curled at the tips. When they are alarmed (which this one seems to be half alarmed), the tentacles can be extended to twice their resting length. Photo by Glenn Marangelo on 7/11/17 near Seeley Lake, MT.