We already have metals that do this, besides Carbon being essentially coal.

Why do people keep suggesting metallic elements right off the periodic table with only element reactions aimed at mimicking real ones? Most of the game's amusing elements aren't remotely realistic, especially the deliberately periodic ones like Hydrogen.

We need more awesomely abstract things that have simple cause and effect, not things people will draw, look at, melt, and be unimpressed or unconcerned with.

Edit: Realistically, to include Carbon, it would need to do something game-changing entirely on its own. Like growing across the edge of quartz like VINE, interfacing with environment variables to enable the game to know where the cursor is, random stuff o_o Anything is possible here, no matter how crazy it is, it doesn't have to make sense. It's almost always better if it doesn't.

..Elements do not become more awesome with time by proxy of being non-descript, Rohan. >.>

'Standard' elements in an amusing Falling Sand game are usually some measure of dynamic, having to stick six items in a mixing bowl to get the desired cake is just not as appealing as sticking one crackling boiling element into another crawly sticky element and getting luminescent gas that forms pulsating radiation barrier that occasionally form bubbles that absorb elements into teleporter channels.

What if you made an element with three identities, one Red, Green and Blue :D Red, when heated, slowly becomes green-colored with little waves denoting temperature diferential. When it reaches its maximum reaction temperature, it react with -itself- in a vibrant shower of black and white to form Green, at its lowest possible temperature. All transforming-red that touches red would become transforming red in an instant, making sure that the change in temperature doesn't leave the puddle with oscillating mixtures of Red and Green.

When Green heats up, it gradually become hot blue-colored, and when reaching its maximum temperature, perform the same transforming sequence of black and white waves in an instant until it becomes Blue. Blue of course, slowly becomes Red much the same way.

..Except, Red is solid, Green is Liquid, and Blue is Powder. What if they reacted to gravity differently at different temperatures, had gradient levels of density and pressure generation, if they teleport when interacted with in specific ways, or even become teleporter channels with themselves?

They could be glowing green fuzzy worms that slowly propagate across the screen by abusing NotNeighbor-styled interaction, seriously @.@