What is the M88A2 Hercules, the heavy US Army vehicle that sank in a deadly training incident in Lithuania?

Source: Business Insider

An M88 recovery vehicle tows an M1A2 Abrams battle tank at a container terminal in Gdynia, Poland. MATEUSZ SLODKOWSKI/AFP via Getty ImagesThe bodies of four US Army soldiers were recovered from a peat bog in a training area in Lithuania. They went missing during a training exercise while operating an M88A2 Hercules recovery vehicle.