[noun]ushi no toki mairi, a traditional Japanese practice where a person visits (参り(mairi)) a shrine at approximately 2 AM in the morning (丑の時(ushi no toki)) in order to nail a straweffigy of a person (藁人形(waraningyō)) to a tree and wish for that person's death
(This term, うしのときまゐり(usinotokimawiri), is a historical kana spelling of the above term.)