It is a "Blue Line Challenge" special effect. The operation process of opening this special effect is demonstrated as follows:

Demonstration equipment: Huawei Enjoy 20, EMI9.1,Tik Tok 14.9.3.

1. Open the main interface of Tik Tok and click Search in the upper right corner.

Second, after opening the search bar, search for the word "Blue Line Challenge".

Third, in the search results, click on the special effects props.

4. As shown below, the Blue Line Challenge will have two props. Click on either one.

5. In the pop-up prop interface, click the picture below to use props.