Doomsday is a black sorcery that builds a pile, and the pile usually wins through Thassa's Oracle, with Street Wraith cycling and cantrips helping them dig. Consign to Memory can't counter Doomsday itself, since it is neither a triggered ability nor a colorless spell. It can counter Thassa's Oracle's enters-the-battlefield trigger, which is their win condition, and it can also hit their colorless spells such as Lotus Petal and Lion's Eye Diamond. Pithing Needle is left out because it only stops activated abilities and does nothing to Oracle's trigger. We trim a couple of Lotus Petals for more disruption, since this matchup is a race to disrupt their one key turn rather than a grind.