Seventeen-year-old singer and songwriter Billie Eilish performed two of her popular songs on the premiere of Saturday Night Live! on September 28. Her eccentric performance on the song Bad Guy, where she appeared to be walking on the walls and the ceiling (video above), took Twitter by storm.

Here’s how Eilish pulled off the stunt:

Eilish also performed another of her famous songs, I Love You, along with her brother Finneas O’Connell.