In the Dungeons & Dragons fantasy role-playing game, the yrthak is a huge magical beast that is somewhat akin to a reptilian bat. It resembles rather closely a gigantic pterodactyl. The creature is twenty feet long and has a wingspan of about forty feet. It is green in color and lacks legs, only having wings. The creature has a dragon-like plate at the end of its tail and a feature akin to a large dorsal fin on its back. The yrthak has a few short spikes on its head and does not have eyes. It requires a special sensory organ in its tongue to see. Also, coming from its head is a lance-like protrusion known a "sonic lance." The yrthak lives in temperate mountains.