Korean War Museum, Archive number 2020120177. The description is: It is the Tiger Brigade medal. It is in the form of a circular medal attached to a small number. The diameter of the medal is 6.2 cm and there is a clothespin on the back. A roaring tiger is engraved on the front of the medal. It was awarded by the US military in charge of the guerrilla Tiger Brigade, which was based in Ganghwa Island 강화도 under Unit 8240 of the UN Command during the Korean War, right before it was incorporated into the ROK Army immediately after the ceasefire. The original picture source is the Korean War Museum.
I have not been able to find anything additional regarding this medal. It does, however, present an appearance very similar to the Order of Military Merit, 2nd Class, 1951 Series.