LE SSERAFIM 'AEIOU' Official Visualizer

In the Korean comments

One comment calls the final sequence the 핌파벳 (the “Fimphabet” pun) ending—a playful blend of 르세라핌 (LE SSERAFIM) and “alphabet” prompted by “AEIOU.” Kyocera Dome is also on commenters’ minds: one reads, in translation, “AEIOU at Kyocera Dome?! That’s wild.”

What the words mean

가즈아 (gajeua, an emphatic “Let’s go!”) is an excited internet-style stretching of 가자 (gaja, “let’s go”). In “Kyocera Dome, let’s go,” it works as a casual, exaggerated cheer rather than a different verb.