(Melee Attack / Skill)
To help you around "bellystab," I’ll assume you mean designing a gameplay mechanic, ability, or item (likely for a role-playing game, action game, or roguelike). bellystab
A laparocentesis or abdominal paracentesis involves inserting a needle into the abdominal cavity to sample fluid for diagnostic purposes. While not exactly a "stab," it involves penetrating the belly to collect a sample. (Melee Attack / Skill) To help you around
The abdomen is the "soft center" of the human body, containing vital organs like the intestines. Striking here represents a piercing of the character's core, often used to humble an otherwise invincible hero or villain. bellystab