Haul was an announced Arcade game that was planned to be available on Grok's page. However, it was never released before My LEGO Network was shut down.
The MLN Arcade page gives the following information about the game:
Haul Arcade Game
This My LEGO Network Arcade game requires some heavy lifting! Create a mind-bending platform puzzler for your friends to play through. Place gates, triggers, bricks and ladders to make your game unique. Coming Soon.
How to Obtain[]
It was implied that Haul would be obtainable from Grok's page, but My LEGO Network was shut down before it became available.