It’s Heidi Klum’s costume!
(Most scary Halloween costume by Heidi Klum.)
She’s trying to be Kali:
(Hindu goddess associated with death and destruction.)
Read more about Kali at IndHistory.com (image is from here).
Kali, also known as Kalika (Bengali: কালী, Kālī / কালিকা Kālīkā ; Sanskrit: काली), is a Hindu goddess associated with death and destruction. The name Kali means “black”, but has by folk etymology come to mean “force of time (kala)”. Despite her negative connotations, she is today considered the goddess of time and change. Although sometimes presented as dark and violent, her earliest incarnation as a figure of annihilation still has some influence. More complex Tantric beliefs sometimes extend her role so far as to be the “ultimate reality” or Brahman. She is also revered as Bhavatarini (literally “redeemer of the universe”). Comparatively recent devotional movements largely conceive Kali as a benevolent mother goddess. (Source: Wikipedia)
Heidi Klum is blue!