The August 20 nuke (or August 21 nuke depending on where you live, also called 8/20 and 8/21) happened on August 20, 2020 at 8:45 PM PDT. Dkaih35 gave everyone admin. Everyone was @everyone-ing for about 2 minutes until everyone was temporarily banned.
Though Dkaih was the one who executed it, Gamer and Riemann were also in on it.
Gamer released a DM conversation between him and Dkaih, which can be viewed here.