The Undies is a "suit" players can unlock in Marvel's Spider-Man. To unlock it, players must complete all missions up to and including Pax in Bello, as well as all side missions and citywide activities on the map.[a] This is the hardest suit to unlock due to the time-investment.
The suit comes with the Equalizer special power. When activated, this suit power enables Spider-Man to take out enemies with a single blow. There is a trade-off, however; the punishing rule also applies to Spider-Man, which means enemies can also take him down in one hit.