the first wonder festival happened in 1985 and the original mascot was a winged green haired girl (i'm still not sure her name) here is a pic from a twitter post that SERPENTYLETORC sent in my discord! the post: twitter.com/col...
it seems she was the mascot but i'm not sure for how long, as wanda appeared in 1997. i have no idea if they had any other mascots after green girl and before wanda, and it's possible wanda came in before 1997 but it's the oldest pic i can find
and then reset came in in 2001
wanda was drawn with her in 2006 probably in an homage to her
here are some alternate pictures of it i took that are from the mizutama keinojo art book!