This is a meme about Chinese.This is a homonym.
My English is very poor.So it's hard for me to explain.
But I tried my best,
"暮"It means Twilight.
"狗"It means Dog.
"瞪"It means to stare eyes.
"呆"It means Shock.

This is a Chinese four-word idiom-"目瞪口呆".It means Stunned.
And the pronunciation of Twilight（暮） in Chinese is the same as that of eyes（目）.
And the mouth（口） is close to the dog（狗）'s pronunciation.
So, can you get it?