One of the new mounts datamined in Patch 10.0.5 is the Crusty Crawler, a new crab mount! The Crusty Crawler will be obtained through the new The Trading Post. The Crusty Crawler is a blue recolor of the Snapback Scuttler, the mount reward from the Undersea Usurper Nazjatar meta achievement.
NEW Crusty Crawler
Description: This rare giant crab has taken a break from its nautical nonsense deep under the sea to explore the surface.
Source: Trading Post