Crochet a Bobble-
A bobble is usually a group of several treble stitches,TR, or longer ones,joined at both top and bottom.It is often surrounded by shorter stitches and worked on a wrong-side row. ( A three treble bobble is illustrated here.)
Step 1: * Wrap the yarn around the hook, insert the yarn where required, pull a loop through. Wrap the yarn around the hook, pull through the first 2 loops, repeat from * two, (or more) times in the same place. Wrap the yarn around the hook and pull through all loops.
Step 2: Work one chain to close and form the bobble.