'''Season 2, Episode 14''':
!The Bishop Revival
A German scientist develops a virus capable of only targeting and killing people with specific genetic traits. When the Fringe team investigates, Walter realises that the killer is using scientific concepts and formulas developed by his own father, Dr. Robert Bischoff, a German scientist who passed information to the Allies during WWII before immigrating to America. The Fringe team find the scientist's lab just as he's left to plant virus bombs at a conference for world tolerance: they manage to find the bombs but can't locate the scientist. Walter, driven to [[TranquilFury tranquil fury]] by the scientist's use of his father's theories, creates a new strain on the virus that only targets the scientist himself and releases it at the conference, killing him. As he dies, the scientist points to Walter and calls him a traitor. At the end of the episode, one of Walter's old photos of his father reveals that the scientist was a Nazi who has somehow lived to be over 100 years old without ageing.
!!Tropes found in this episode:
* TheAgeless: The German scientist.
** Creating the seahorse signature is quite implausible with today's technology, and was certainly impossible in 1943.
*** The idea is that the German scientist spent the last 70 years or so developing the toxin, and made it as his twisted fuck you to Walter's dad. Even without that, considering Massive Dynamic, Walter and ZFT, making a chemical weapon with a carbon structure that looks like a seahorse is the least improbable thing.
** DNA was actually discovered Swiss physician Friedrich Miescher in 1869, well before Nazi Germany.
*** The theory of DNA containing a cell's genetic information, however, was first proposed by Oswald Avery in 1944 and was generally accepted only after Francis' and Crick's discovery of the now-famous double-helix structure (with its implications for DNA's duplication mechanism) in 1953. So a Nazi scientist doing DNA-based genetics would indeed have been ahead of his time.
** Peter thought his grandfather immigrated in 1933, which he described as "long before the Nazis ever took power", but in actuality the rule of the Third Reich and Adolf Hitler in UsefulNotes/NaziGermany started in 1933.
** Someone poisoned by cyanide actually has cherry red blood, not blue blood.
* BitterAlmonds: Averted, although I am uncertain what the cinnamon scent was meant to indicate.
* CarryingACake: Averted, the three layer wedding cake being carried in the opening scene is never shown again.
* CoolOldLady: Eva Staller. From what little we saw of her, she was nice and cool for someone who survived the holocaust.
* DrivesLikeCrazy: Walter
* KarmicDeath: The Nazi gets killed by his own chemical weapon by Walter, the son of the guy who worked against him, after he tried using the chemical weapon on Walter himself.
* LegoGenetics: Most of the features described by Walter, like height and weight, are a polygenic trait that also can be strongly influenced by environmental factors.
*** But that doesn't mean the chemical weapon couldn't be used to target people with a genetic predisposition to being thin or fat.
* PoliticallyIncorrectVillain: A Nazi Scientist who created a chemical weapon that targets people according to pre-programmed genetic traits, and he tests at the wedding of one of his Jewish victims. Needless to say, it's satisfying when Walter kills him with his own weapon.