What is "merrshaulk"

In the Dungeons & Dragons fantasy roleplaying game, Merrshaulk is the yuan-ti deity of poison and somnolence. "Merrshaulk" is likely a dwarven rendering of his name; the yuan-ti pronounce the name more like "Mi-Shao-Shur," although they view it as too holy to pronounce around outsiders. The god's holy symbol is a cobra's head.