The blarg pyamus is a split from its ancestor, the binucleus pyamus, and has not changed very much. It has gotten slightly larger, due to a large food source. It also now has the ability to absorb methane, just like its ancestor absorbed the dead animal matter that floated its way. To gather the methane it sits at the edge of the underwater salty-brine methane lake. They stay at the edge so they can breathe as well as absorb the methane.
Picture by Hydromancerx.