The planet of Ultra Megalopolis was first discovered by the rest of the galaxy not as a result of its thriving industrial civilization, but through a prank played by one of that world's most common and popular Ultra Beasts. Astronomers on many worlds noted the brief appearance of a strange purple light, inexplicable through stellar evolution, which was so bright it overshadowed the planet's own distant star. The Poipole's purple beacon was short-lived, and soon turned off by Ultra Megalopolis' dominant species, who were dismayed by its massive power consumption, yet the short-lived light continues to troll astronomers as it travels throughout the galaxy.

Poipole are born pranksters, and while the purple beacon was their most legendary trick, it is far from their only one. The fluids Poipole spit to defend themselves are even more adhesive than they are toxic, and although they likely evolved them for self-defense, they more often use them for every trick that a mischievous child can pull off with a can of superglue, plus a few which require significantly more height and aim. Curiously, despite or perhaps because of this mentality, Poipole have become the beloved companions of the so-called Ultra Megalopolitans, whom other aliens typically regard as excessively straight-laced and professional.

Few Poipole have ventured through the Ultra Wormholes as far as Earth, and most who did were too busy working with their trainers to get up to their usual antics; the one or two to find themselves a human trainer inevitably proved challenging to raise, at least if one wished to win pokemon battles or command a close-knit team. Yet a surprising number of reports of Elgyem encounters in the vicinity refer to needle-like probes otherwise unattested in Elgyem technology, and describe the "Elgyem" in question as purple.