New World arboreals that skipped urticating hairs entirely, which means they defend themselves by being faster than you instead. P. irminia, the sun tiger, is the one everyone starts with.
Speed is the whole conversation. These animals move in a straight line at a rate that catches experienced keepers off guard, and the standard advice to work slowly and calmly does not apply because they will simply be gone. Rehouse in a bathtub.
They grow fast, breed readily, and eat well, so supply is deep and prices are among the best value in the hobby for an animal this attractive. P. victori is the outlier, still commanding a substantial premium on thin production. The rest of the genus is a case study in what happens when breeding gets easy: steady, unglamorous, low prices.