.-yuki-.: help what is going on with animation mode T0T

Fruity: two potential reasons i can think of: the area that is transparent was originally coloured black, and if so: it sometimes doesnt seem to like the colour black. using any colour slightly lighter than black should fix this.
otherwise: you didnt set the room settings for the board to have a white/grey background. Then, since it would be set to transparent, with each new frame the ones prior would be shown behind it if you didnt colour in an area (such as with the hair)

.-yuki-.: the transparent part was not colored black and i did set the room settings to make the board white