Found this Saddleback Caterpillar (Acharia stimulea) in Yucatan, Mexico.

The hairs are allegedly capable of injecting venom with effects that can range from irritation and nausea all the way to severe reactions in rare circumstances. I did not test.

In this image you can see the actual head and eyes protruding from underneath its saddleback costume.

A more common view of this caterpillar is from its back side, where you can see its pretend “scary big eyes” that it uses to scare off some predators.

Here are some other viewpoints: