A caterpillar makes a strange reaction to defend itself.

This is the final instar caterpillar of a Sunbeam butterfly, just prior to pupation. The caterpillars are remarkable enough for the twin periscopes on their hind ends which contain tentacle organs. When threatened, the caterpillar (including at this prepupal stage) telescopes these structures outwards of their sheath in the form of a bouquet of hair-like tentacles which whirl around. This is presumably a defensive mechanism designed to alarm a potential predator, but it is hypothesised that they may also have a volatile secretion dissipation function as well.