1. What does it mean?
띠용 is a playful reaction to something puzzling or unexpected. It can appear on its own with a question mark, in a caption, or as a spoken response when a situation makes you do a double take.
Also written or said as 띠용?, ttiyong
2. The nuance
Usually lighter and more cartoonish than a serious complaint. It does not name a specific emotion every time: the surprise may be amused, confused, or mildly annoyed. No single inventor or first-use date is established here.
3. Examples
“띠용? 분명 혼자 찍었는데 뒤에 친구가 있네.”
Huh? I thought I took the photo alone, but my friend's behind me.
“빈 통인 줄 알았는데 안에서 알람이 울려서 띠용했어.”
I thought the container was empty, so I did a double take when an alarm went off inside it.
Sources
In4 Blog: Korean internet expressions
References support the meaning and usage. Example sentences are written for NoCapWiki.