Yu san 雨伞 (umbrella)

When it's raining, and we talked about opening the umbrella 雨伞 (yu2 san3), Benja started singing:

一闪一闪亮晶晶
满天都是小星星

一闪 (yi4 shan3), yes, it does sound like 雨伞。

Good sound association and singing, Benja!