As part of The Indigo Disk DLC, you'll need to take down the BB Elite Four members scattered around the four biomes of the Terarium. Crispin is the Fire-type trainer that can be battled at the Savanna Plaza, located in the southwestern section of the Savanna biome. After donating 50 BP, you'll be able to take on Crispin and his team of (mostly) Fire-types, but before that, you'll have to complete a short trial to gather ingredients to make a super-spicy sandwich.