Marisa Catherine Lock (1977 or 1978), known professionally as Blue MC, is an Australian rapper and electronic music singer.

She wrote and recorded vocals for Australian producers, Bionik World, Superfluid and Hermitude.

During time in London she wrote and featured vocals on two songs for United Kingdom electronic duo Hexstatic on their studio album, When Robots Go Bad (2007).

She returned to Sydney in late 2005 and joined the electro-house and dance music group the Potbelleez with Dave Goode on programming and DJing, Jonny Sonic on programming and DJing and iKid (Ilan Kidron) on vocals and guitar.

At the APRA Music Awards of 2011 she was nominated for Dance Work of the Year for co-writing "Hello".