Dragonman

A dragonman is a human (possibly other humanoid races) fused with a dragonspawn. They were first introduced in World of Warcraft: Cataclysm.

It would appear the fusion process lowers the creatures' intelligence. Failed fusions appear as aberrations found in Blackwing Descent, twisted creatures most resembling plague eruptors used by the Scourge.

Trivia

 * At BlizzCon 2010, it was mentioned in an offhand comment something called a "dragonman" was based on unused concept art for a scrapped idea for a playable race. These are likely that "dragonman" as that is their model's name.
 * The Art of World of Warcraft contains concept art for dragonmen, although they have no "horns".
 * Dragonmen use the same model base as alliance worgen and therefore use the same animations.

Speculation

 * It's unknown if the fusion requires a dead or alive dragonspawn, however the corpse of one was used to create Maloriak.
 * It appears that the fusion process was a failed experiment by Nefarian to create loyal minions with their original intellect.