ㅇㅅㅇ is a cute face emoticon in Korean, roughly equivalent to OwO in English. A different variation ㅇㅂㅇ exists, which could be thought of as UwU. It is hated by many people, due to reasons seen with OwO.
The fisher's S, written as Ş or ş. Has a hook below for fishing, hence the name. It is now obsolete in many places due to better fishing hooks being available such as Ç.
Person 1: Hey! What's that fisher using?
Person 2: That's the Ş, hard to see nowadays.
Type of a laugh or a suffix to a word to make it have more laugh. When used as a suffix, it is usually used on a proper noun, but that isn't always the case.