Assuming you're honestly asking and not making a joke: The blue eyes and multiple references to Jessica and Umineko in the text make it pretty clear it's a reference to the cosplay concert scene in the series.
e22big said: how do you know she is not the real Marisa?
Poliwag said: Assuming you're honestly asking and not making a joke: The blue eyes and multiple references to Jessica and Umineko in the text make it pretty clear it's a reference to the cosplay concert scene in the series.
Pata-Hikari said: Besides everybody knows witches don't exist. So it can't be the "real Marisa."
The "real Marisa" has yellow eyes, otherwise no difference.