fabruncle
When a guy has a kid with his sister. That kid is his brother and his dad. He's the worst kind of family man.
My dad's sister had a kid with him. That kid is my brother and my dad. My dad is a total fabruncle.
My cousin is my dad's kid. But my dad is also my cousin's dad. He's a fabruncle.
My uncle's kid is my brother. But my uncle is also my brother's dad. That's a fabruncle.