f(x)'s Krystal revealed a past picture comic that showed her funny facial expressions and attracted attention. 

Krystal wrote on her me2day on Saturday, "This is a picture from a while ago. This was when I ate Sulli," and uploaded 2 photos. 

Krystal took a picture with Amber and opened her mouth wide behind Sulli, as if she was going to eat her. 

Internet users commented, "It's funny that she looks like she's going to eat Sulli," "I can feel the energy of the lively girls," and "It looks like the relationships between the members are good."

f(x) is a group that debuted in 2009 with the single album LA chA TA. They have gained popularity with their unique songs.