What's That Mark on U.S. Figure Skater Mirai Nagasu's Thigh? 

Mirai Nagasu of the United States performs in the ladies single skating free skating in the Gangneung Ice Arena at the 2018 Winter Olympics in Gangneung, South Korea, Monday, Feb. 12, 2018.

After figure skater Mirai Nagasu became the first women's skater to nail a triple axel in an Olympic event, all anyone could talk about were the strange markings on her upper thigh. Was it a tattoo? A bruise? Some sort of kinesthetic tape?

But before we get to that, let's recap her performance from Sunday night in the women's individual portion of the team event in Pyeongchang, S. Korea.

The 24-year-old Nagasu wasn't just the first American to land a triple axel at the Olympics, she was also only the second American woman to land the jump in an international competition. The first was completed by Tonya Harding — nearly 27 years ago. The only other women to land the jump in an Olympic competition were Midori Ito and Mao Asada, both from Japan. Here's the amazing feat:

Be sure to watch to the end to see Nagasu's emotional reaction to skating a clean program.

But that wasn't all skating fans were talking about. Everyone wanted to know whether Nagasu was sporting a bruise, a tattoo, or KT Tape:

Twitter literally blew up with fans asking this question.

You can get a better look at it here: