You can easily make your own with a canvas, a paint brush, masking tape, and three colors + white acrylic paint. Just tape up your canvas every which way, paint a gradient of each color in the taped segments and remove the tape
Illustration by Jason Levesque. I love the colors and the idea of a jellyfish brain. Jellyfish don't have brains, though. I wonder if that's part of the statement the artist is trying to make, but I'm probably looking Into it too much.