>>/5181/
That's cool!
What species is this? Tobacco hornworm (Manduca sexta)?
Doesn't look like a hummingbird moth (Hemaris sp.) caterpillar but we aren't familiar with them, especially those from the Americas. All I can say for sure is that it's some Sphingid.
Haven't seen any noteworthy caterpillar in years, it's sad.
Assuming it's in the last instar, wandering off the foodplant to find a safe place for pupation isn't unusual for caterpillars. They generally try to hide whenever not feeding because many birds are smart and check plants with visible damage for the culprit.