Ghoul Experimic is an NPC at the Cursed Ship. He is located in the kitchen (near the Ship Officer area). To use this NPC, you will need 100 Ectoplasm and a Hellfire Torch. This NPC will change your race to Ghoul once you've paid him with the items mentioned before.
IMPORTANT NOTE : After purchasing the Ghoul Race you can equip it again when you change your Race, similar to a Fighting Style, at no cost to you. The Race version (V1, V2 or V3) will also stay once evolved.
Note: If you don't have the requirements for ghoul race he will simply say "Ahhhhh, Guashiem..." And if you further prompt speech, he will say, "It's so cold..."