Whether it's vocals, dancing or any other metric you wanna use.
For Mamamoo, this one takes the cake with the vocal runs, high notes and adlibs.
Another vocally-challenging song but additionally, the members having fuller/deeper vocal tones really sets the mature and sexy vibe. Moonbyul's rap verses (especially the 2nd one) seems tricky too.
Used to wonder why Mamamoo never did those gg song swap stages or why their songs were rarely covered on idol training programs.