There are at least three artists with this name (from most to least active) :
These are photos from concerts where Grimalkin played, so they may be of other bands that played the concert as well.
A Day of Clarity 2016 May 21, 2016 Adelaide, South Australia, Australia Uploaded by Stan Stan Stan
Scumfest 2015 Nov 14, 2015 Adelaide, South Australia, Australia Uploaded by Stan Stan Stan