The jellyfish is knitted in the round, from the top down. There is a little light stranded colorwork involved here. I didn’t write out a chart because it just didn’t seem necessary. The instructions use counted stitches instead. You could always leave out the second color if you find it intimidating, or use a variegated yarn to give your jelly some color.
You will need 38 yds of your main color, and 10 yds of your contrast color, as well as knowledge of knitting in the round and simple increases and decreases.