Washable fake blood

[IvaNighSpare]

Hello there, seeking your advice.
My daughter is making her own Halloween costume and going as a "corpse bride". She wants to wear a white dress of hers, but, if possible, would like to splash it with some fake blood. But she wants to be able to wear the dress again (sans blood) another time.
Does anyone know if I can buy or make something that won't permanently stain the dress? Or have any other ideas? (I've tried "why don't you pick a different dress / costume" line but that won't wash with her, pardon the pun).
Much appreciated.