A mix between a platypus and an octopus. Nobody knows, nor cares how this abomination was created. It has the head of a platypus, and the body of an octopus (tentacles).
Guy1: Hey Guy2! Look what I found! A platypoctopus!
Guy2: Thatsa dildo.
A Platycorn is a mythical creature with the lips of an obese platypus, the horn of a unicorn, and the body of a retarded goat. The Platycorn made its first appearance during an incredibly dirty game of drunken Pictionary.
Ivan tried to draw a goat, but he's an alcoholic who sucks at art, so instead he drew a Platycorn.
Something that is apocryphal - "of dubious veracity or authenticity" - like a platypus, but then also like the platypus, turns out actually to be real, but super weird.
The rumors that Mitch's girlfriend was one of a set of conjoined triplets turned out to be platypocryphal -- unbelievable, but true.