It's a little upsetting to see that Tahu has such intricacy for every detail and the lava is just a big, flat plane. A secondary colour in some specific spots like circles slightly contorted to match the curve might've improved it, but it just looks like he's surfin' on the fanta sea, so you know it ain't real life.
Linework is very good, so is the colouring (although the limbs look weird with the lighter portions being a pinch too white). The head is a fair bit small on the body, but that was probably due to fosucing in actual human proportions which would work in most cases, but this is a Broccoli man we're talking about. Nice work, from both of you!