Blood banks carefully screen patients and donors by their blood type: A, B, AB, O. They also look for rarer blood types that might lead to transfusion problems. But some blood types remain a mystery.

Jaz Sinclair, Chance Perdomo and Lizze Broadway get gory in Prime Video’s new look at “Gen V,” the upcoming spin-off of the superhero drama series “The Boys.” The new teaser trailer shows the ...