Walrus/Groon is a collaborative 12" EP between Merzbow (Japanese noise musician Masami Akita) and Japanese experimental doom band Boris, released on the Los Angeles-based Hydra Head label in 2007. It was first sold at the 2007 South by Southwest festival in Austin, Texas.

The walrus (Odobenus rosmarus) is a large flippered marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and sub-Arctic seas of the Northern Hemisphere. The walrus is the only living species in the Odobenidae family and Odobenus genus. It is subdivided into three subspecies: the Atlantic walrus (O. rosmarus rosmarus) which lives in the Atlantic Ocean, the Pacific walrus (O. rosmarus divergens) which lives in the Pacific Ocean, and O. rosmarus laptevi, which lives in the Laptev Sea.

The Walrus HULA was a proposed Hybrid Ultra Large Aircraft. The goal was to create an airship capable of traveling up to 12,000 nautical miles (about 22,000 km) in range, while carrying 500-1000 tons of cargo. In distinct contrast to earlier generation airships, the Walrus HULA would be a heavier-than-air vehicle and would generate lift through a combination of aerodynamics, thrust vectoring, and gas buoyancy generation and management. As of April 2006, the project was in danger of termination. The 2007 Budget request from DARPA called for the termination of work on WALRUS after completion of the current Phase I contracts.