Geysers, Mudpots, & Volcanoes

As part of the Caves & Cliffs update, there should be mountains that generate with huge lava pits at their tops at least 30-40 blocks deep. Occasionally, it would shoot huge amounts of smoke into the air as long as the chunk it's in is loaded. It would mostly  be made of  stone and maybe blackstone and basalt surrounding the lava pit.

Also there should be a biome littered with craters of boiling hot water, which would emit steam cloud particles. Boiling water would come from a source block being on top of magma for long enough, say about a minute or two. the water would become more cloudy and less transparent due to bubbles forming in the water, and this can be scooped up in a bucket. if boiling water is placed off of magma, it will cool down to regular water after a few minutes, and putting it on ice will immediately cool it down. These steaming hot geysers would be comprised of maybe a new block, limestone, or solid sulfur. They could also generate in the large caves underneath the biome. 

In this same biome, there would be pits of thick mud, which would be similar to quicksand. A cool addition with this would be the player being covered in brown mud for a while after they got out, and it going away if they swim in water or its raining. The mud could be scooped up in a bucket, and if the player were to place the mud on magma, it would become a dry mud block. Dry mud blocks could generate around the mudpots, or just spawning in small patches in the biome.