Spelunk is the most removed mole from society ever seen. He hoards a massive amount of treasure and anyone that gets near it will never be able to see the surface world again. After Sonic saves him from being crushed by a falling boulder, which was from Robotnik digging into the cavern, Spelunk has a change of heart and allows Sonic and Tails to leave. He even assists them in getting his treasures back from Robotnik. Having realized the true value of friendship, Spelunk uses some of his treasure to buy Chili Dogs for Sonic and Tails.
Initially, Spelunk was mean, selfish, greedy, and was not trusting of anyone. He would do anything in order to keep the treasure buried in his cave for himself as he regarded it as his only friends, and was willing to capture and destroy anyone who trespasses the Marble Zone (regardless if any trespassers were intent in seeking his treasure or not). However, after Sonic risked his life to save his, Spelunk realized the error of his ways, becoming much more friendly and charitable.