DDL-920, which apparently looks like this: https://www.probechem.com/userfiles/product/PC-22875.gif

"DDL-920 is a potent, selective and brain permeable negative allosteric modulator (NAM) of the γ-aminobutyric acid type A receptors (GABARs), inhibits parvalbumin (PV) expressing interneurons (PV+INs) and consequently enhances γ-oscillations both in vitro and in vivo."

https://www.probechem.com/products_DDL-920.html