Forum:Malefic question

Alright >.< I've looked all over to figure this out to no avail, so I've read up on Malefics, i have a deck and im not saying this out of lack of searching, but. Lets say skill drain is on the field, i summon a malefic, then i play book of moon on that malefic, can i summon another malefic then flip the other up? it says only one malefic can BE FACE UP on the field and book of moon would change that .-. so ya curious, plus if it DOES work, are both destroyed or do i choose one to stay and another to destroy? and thanks in advance for replies just do something so i know its a reply and such :P