Sultai Reanimator wants to fill the graveyard and cheat back huge threats like Bringer of the Last Gift or Overlord of the Balemurk, so hitting the graveyard and racing fast is the plan. Rest in Peace is a premier answer here, exiling their graveyard so Bringer of the Last Gift and other recursive plans lose most of their value and threats can't return via graveyard synergies. Mossborn Hydra provides a quick, resilient clock that doesn't care about their removal-light, value-oriented gameplan. Practiced Offense and the extra Icetill Explorer copies are too slow when we want to pressure them before their engine comes online.