I pronounce it the spooky way (maSCAREuh). I grew up in Hawai'i, Missouri, and Texas--my accent is primarily Midwest with a touch of Texas (and some Hawai'i accent when talking with my relatives there).
Mass-SCAR-ah, South coast of England, accent varies from Sussex-Hampshire to RP, but regardless of how posh (or not) I’m sounding, the SCAR stays the same.
Scar - British RP
Scare - Scouse and other British dialect accents with longer vowel sounds
Marse-Scurruh - Westcountry English dialect accents. (Pirate accent)
Mass-scare-a, Bay Area of California born and raised but according to that "Where Is Your English From" map poll people were doing a few months back I may as well be Judd Hirsch.
Defo 'mas-SCAR-ah' everywhere I've lived (Wales, England & Scotland). Whilst my American parents also say it 'mas-SCAR-ah' as a result of living over here so long, I have heard it pronounced 'mas-SCARE-ah' in American shows pretty broadly east-coast & west-coast.
Mass-SCAH-ruh (R goes in the third syllable). NYC> UK> upper East Coast, with stops in the Midwest and South but I refused to allow my vowels to be distorted, sorry not sorry.
SCARE-uh, mostly Minnesota. My mom didn’t talk about makeup, so it’s a word I heard only in public and on the media, so I’m not sure if that’s really how it would be organically pronounced by others.