P.U.S.S-E #
This page refers to the concept within the ARG, not the song.
P.U.S.S-E is short for Pineal Upregulation Synthetic Substrance Enhanced, as seen in promotional posts. It is based on DMT, as confirmed in the song.
“What would you do for P.U.S.S-E?”
P.U.S.S-E seems to be a drug, implied by instagram posts, a pill bottle at the end of the spectrogram in the song and additional promotional information. The stylization of puss-e (like P.u.s.s-e) is different between the tracklist and the instagram.
Promotional post from the BMTH instagram, see page on social posts
The small text on the access card on the main ARG page also recommends two doses of P.U.S.S-E a day for this patient.