Halloween // I need some costume ideas plss

So I turn 18 the day after Halloween so I’ll basically be celebrating my birthday on Halloween, which means I need to go BIG!!(but it also needs to be school appropriate bc we have a costume party on the last day and I’m NOT buying two costumes unless I can use parts of one for the other). Does anyone have any suggestions??

I was thinking Christine daee (phantom of the opera ml) or that one from princess diaries (yk the one) but I’m open to anything I can get quickly Thxx