S5E9: The Sting
Fry touched the royal jelly in the space hive,
leaving an imprint of his D.N.A. and brain waves.
Then, when it spilled on the couch,
it recombined with trace amounts of Fry's hair and skin--
And blood! Don't forget about Fry's blood.
Yes, Bender, thank you. In short, the various fluids Fry left in the couch...