Spier-Girl (May "Mayday" Parker) is a fictional comic book superheroine active in an alternate future of Marvel Comics' shared universe, the Marvel Universe. The character was created by Tom DeFalco and Ron Frenz as a spin-off of the Spider-Man character, and first appeared in What If (Vol. 2) #105 (1998). She later acquired her own ongoing comic book, Spider-Girl, written by DeFalco and drawn by Frenz and Pat Olliffe, which is the longest-running superhero book with a lead female character ever published by Marvel.