According to a Joystiq report, Sleep Ninja, the makers of Monsters Ate My Birthday Cake, are being accused of stealing art from Athens, Greece-based illustrator Ilias Sounas.

Sounas has posted the allegedly offending art on a blog alongside the art he created in 2012 for Karios Games’ MonsterUp Adventures. The game’s map is the main sticking point, and Sounas compares the two maps on his blog, noting similarities between the design of trees, hills, waves, islands and shadows, as well as the general layout of the maps. He demands that Sleep Ninja remove the offending Game Map and replace it with different assets.

While the two maps may look different at a glance, a close-up look makes it evident that numerous elements of Monsters Ate My Birthday Cake’s overworld are directly cribbed from Sounas’ work. It’s always disappointing when game makers use the work of a colleague without permission, and we’re hopeful that Sleep Ninja and Cartoon Network, the game’s publisher, will rectify the situation soon. As of yet, Sounas has not heard from either the developer or the publisher in regard to the accusations, but Cartoon Network told Joystiq they are, "looking into this" and, "will be in touch with a response."