Blizzard has launched a month-long blood drive to celebrate the release of Diablo IV's second season, Season of Blood. There will be three tiers of rewards that will unlock as more people donate, with the final reward being a sweepstakes for a custom liquid-cooled PC infused with human blood.
Or just a drop or two added or some shit. I think they worded it that way so people think the coolant is replaced with blood, which it obviously is not.