Last year my son asked if he could be a pumpkin for Halloween. Having only a couple of days left to complete the task, I found some very chunky orange wool, and with a large circular needle I cast on around 100 stitches, ribbed for 8 rows, then increased in every stitch to make it balloon out. After knitting to his measurements I worked armholes by splitting the circle in two, casting off a few stitches on either end of each panel, knitting and then rejoining in the round to make a neck hole (which I also did in ribbing).
The top was a simple beanie with a brown top and some green, spool (French) knit pieces on top of twisted pipe cleaners to look like vines.
I knit a matching costume for his sloth toy, for good measure : )
Using such chunky wool it really didn’t take too long to make the costume. To avoid an all-night knitting session like I had to pull, give yourself a week to complete the task.