By-product

n.

1.

A secondary or additional product; something produced, as in the course of a manufacture, in addition to the principal product.

Noun	1.	by-product - a secondary and sometimes unexpected consequence Synonyms: byproduct
	2.	by-product - a product made during the manufacture of something else Synonyms: spin-off, byproduct

byproduct, consequence, effect, epiphenomenon, event, issue, outcome, result, upshot