H.O.T's Kangta walked down memory lane with some of his group's merchandise, but what especially grabbed EXO's interest was his 'DNA necklace' on the premiere of 'EXO 90:2014'!

Kangta showed off his 'DNA necklace' from back in the '90s, as he explained, "Our members' DNA was extracted... We got a sample of our blood and our DNA was extracted, and it was used in the necklaces," showing the silver emblem with a DNA strand shape embossed on it.

While the other EXO members showed their awe at the unique idea, understanding what Kangta meant, D.O looked on bug-eyed with a bewildered expression.

D.O. blurted out with big eyes, "So you put your blood inside that necklace?" This prompted Kai to hilariously slap D.O on the arm as he explained, "No, they put the shape [of the DNA]." 

While the other members burst into laughter over his 4D question, which suggested that the H.O.T members put blood inside every necklace produced, D.O. then followed up with another question, still obviously very curious and baffled.

Curious to understand more about the science of this, D.O once again blurted, "Is the shape of the DNA different for each person?" leaving everyone to freeze in their spot, realizing they were still stuck on the subject of DNA necklaces. Sehun responded, "Is this science class?", and MC Jun Hyun Moo also didn't help as he answered, "I'm not a biologist so I wouldn't know," continuing the laughs.

Check out the hilarious clip below!