"Words that refers to a person or thing that there is enormous popularity in elementary school." is "초통령"(cho-tong-nyŏng) in Korean.
Cho tong ryeong (초 통령) the word that refers to a person or thing that there is enormous popularity in elementary school. It is compound word of initials of elementary school students and (초등학생 primary student / Cho deung hak sang) "Cho (초)", and the President (대통령 / Detongryeong ).
Athletes, such as is likely true character. "Pororo" of animated characters that have been broadcast in Korean Broadcasting System is a typical "Chotongryeong". Also and Kim Yun a players of figure skating, it can be said that the singer PSY which became famous in "Gangnam Style" is also a collection of popular American elementary school "Chotongryeong".