"I am pretty sure his venom could be quite useful if properly diluted. Just to remove bad memories, you know."
-- Newt Scamander (WFT)
A glowing substance extracted from the cocoon of the Swooping Evil (WFT).
References from the canon
Newt Scamander owned a Swooping Evil and discovered that the venom could be used to erase harmful memories. After an Obscurial attack on New York City and rebuilding by wizards, Newt suggested that Frank the Thunderbird could be sent aloft to drop a vial of the venom over New York City so the No-Majs could be obliviated all at once in the ensuing rain storm (WFT).