Based on much of their recent posts, they're playing Regrowth, in which the only variant of this is Mariculture's Molten Experience - the primary use of which is for automation of the Blacksmith's Anvil, which is achieved by having a Mariculture fluid tank containing the molten XP with a blacksmith's anvil beside it, and a blacksmith's assistant on top holding a blacksmith's hammer on the appropriate side to hit the anvil.