Does anyone know what is the stamp between voiceinthefog and thatonecharacter in the Other section? It's the 4th one counting from the bottom

It's called scienceishappening; the obtainment method is (spoilers, obviously lol) to mutate a pet. This uses either the suspicious concoction (obtained mostly through the voice in the fog) or the devious brew (obtained with pumpkins in the Halloween event)

Thank you