CommonFun.calcBuff_7850
function CommonFun.calcBuff_7850(srcUser, targetUser, a, b, c, d, lv)
  if srcUser == nil or targetUser == nil then
    return 0
  end
  local layer = srcUser:GetBuffLayer(187570_THE_ATTACK_DEALS_EXTRA_TRUE_DMG_OF_SELF_HP_:MAX_STACK_2)
  local Maxhp = srcUser:GetProperty("MaxHp")
  local A = layer * Maxhp * 0.5
  return -A
end