Ribbit! I had a blast making this fun wool felt project. I imagine there must be a faster way to make wool felt balls, but I just figured out a way to make them on my own, and built up some arm muscles in the process.
I was envisioning a baby toy or rattle for the frog, so I scavenged the house for a large jingle bell, and found none. I had some teeny tiny jingle bells, so I put 3 tiny bells inside an aluminum cap for cloth-covered buttons and began winding wool roving around and around. Occasionally, I'd tuck wool fibers in using my felting needles, tiny, barbed needles used to mesh the wool fibers together into a felt.
When it would get a bit lumpy, I'd stop wrapping and begin needle felting, jabbing the needle repeatedly and rotating the ball as I went to ensure an even felt. I did this about 3 times before I wrapped the ball with green roving (I used a natural wool roving for the center as it is cheaper than the dyed wool).
After felting the green roving evenly, I formed little green balls for the eyes and attached them, then created little balls of the same, slightly darker green wool for little warty spots on his back. A bright yellow ball of fluff was added for the eyes, then a chocolate brown for the center of the eyes. I decided I wanted him to have a protuberant nose, so I sculpted a mass of green wool to his face until I had a gradually sloping face.
Lastly, I twisted some chocolate brown roving into a long string and needle felted it in place as the mouth. It rattles quite satisfactorily, and even rattles continuously if you roll it across a table because the loose bells inside the button cover tumble as it rolls.
I'm not sure who I'm going to give it to yet, or if I'm going to sell it, but it was fun to make!