沼气

沼 = 召 + 氵 : James II of England (zh) calls everyone together via intercom (召) to gather in the aorta's living room (ao3). He introduces his latest policy to build a pool (沼) in the aorta. As a symbolic start he opens a bottle of water (氵) and pours it on the floor.

Mnemonic symbol: a balloon. The Queen of Hearts is disappointed by her balloons. She expected them to float upwards, but in the space station's bathroom, They float randomly in all directions.