Leaf beetle larva (Chrysomelidae: Cassidinae) from Chiang Mai, Thailand.
Erebid moth caterpillar (Erebidae: Aganainae: possibly Asota sp.) from Siem Reap, Cambodia.
Saddleback caterpillars (Limacodidae: Acharia stimulea) like this one may be beautiful, but one should keep their distance - those spines are capable of inflicting painful stings. (Editor's note: I tend to refer to these as "sweater vest caterpillars.")