Igneous (sometimes known as Iggy) is a confident little hothead. He doesn't know when to stop at something when he's got the motivation or is just feeling very defiant. Get him worked up enough and he's almost guaranteed to do something about it. For Igneous, he won't stop until he's forced to and it causes him to exhaust himself... it's especially an issue when he's caught in a fight because he'll refuse to retreat. Thankfully for him at least, his body is very sturdy. His appearance mimics that of obsidian, giving off a glassy shine under bright light.
Igneous is the second of the first two friends Piff has ever had, and with Bon-bon the three of them are their own little friend circle. Igneous met the other two by literally running into them and hitting them like a rock. He dragged them along with him to help repay a debt he owed to someone else.
Despite his poor control of himself, Igneous's passion goes both ways. He's incredibly supportive to his friends, often to the point of embarrassment for them and sometimes ruining a moment. It's the thought that counts though.