The RBU-6000 is an anti-submarine rocket launcher that was adopted by the Russian Navy back in the 1960s. It was designed to take out enemy submersibles and torpedoes with 213mm rockets.
Recently, however, Russian troops started mounting these weapons on tracked and wheeled vehicles and using them to blow Ukrainian tanks and fortifications to bits.
The following video courtesy of the Russian Ministry of Defense allows you to appreciate the sheer might of this weapon.