Purim
There is a tale in the Hasidic Chabad movement that supposedly Joseph Stalin died as a result of some metaphysical intervention of the seventh Chabad leader, Rabbi Menachem Mendel Schneerson, during the recitation of a discourse at a public Purim Farbrengen. Stalin was suddenly paralyzed on 1 March 1953, which corresponds to Purim 1953, and died 4 days later. Due to Stalin's death, nationwide pogroms against Jews throughout the Soviet Union were averted, as Stalin's infamous doctors' plot was halted.
Lysenkoism
Joseph Stalin supported the campaign. More than 3,000 mainstream biologists were fired or even sent to prison, and numerous scientists were executed as part of a campaign instigated by Lysenko to suppress his scientific opponents. The president of the Agriculture Academy, Nikolai Vavilov, was sent to prison and died there, while scientific research in the field of genetics was effectively destroyed until the death of Stalin in 1953. Research and teaching in the fields of neurophysiology, cell biology, and many other biological disciplines was also negatively affected or banned.