Raving Piranha Plant
From the Super Mario Wiki
Raving Piranha Plants are a species of Piranha Plant that appear in Mario Kart 8 and Mario Kart 8 Deluxe. Raving Piranha Plants occur only in the Electrodrome, where they appear both as obstacles and background characters. They act in the same way as regular Piranha Plants and will bite at the player if they get too close. The Raving Piranha Plants also dance in time with the music and change positions in the Warp Pipes at the end of the course, similar to the Piranha Plants in Music Park.
Raving Piranha Plants are the same shape as regular Piranha Plants, but are covered in small flashing dots. The dots on the white areas like the lips, teeth and spots change color in time with the music, changing between pink, yellow, green, blue and purple, but remain predominantly white, while on black areas such as the head, stalk and outer leaves the color does not change from grey. These dots match the changing colors of the Warp Pipes they appear in.