On the more magnificent side are the plain butterfly caterpillars (Polyura hebe plautus) from Singapore, which have very long and beautiful horns. The dragonhead's helmet is entirely black when the first caterpillar hatches first, and then gradually fades to green as it reaches the last stage before metamorphosis.
And the top picture, by Australian photographer John Horstman, describes the unidentified species found in Pu'er, in Yunnan province in China, showing off a small set of bright red horns, which may be useful for surprising predators.
But my choice is the caterpillar of the queen butterfly (Euxanthe wakefieldi), found in South Africa and parts of eastern Africa. His dragonhead helmet was blowing a fishing rod, with the outer horn stretching much longer than the second, and the black crown of thorns crossing between each horn. In addition, his entire body, including head and horns, is trimmed on white or golden borders that offset the rest of his dark green body.