There are a couple different scenarios that can happen when a check is returned for non-sufficient funds. 

Your check: Cashed or deposited by someone else
When you write a check and there's not enough funds in your account when it's presented, this is considered non-sufficient funds (NSF). When a check is returned due to NSF, it's returned to the payee that deposited the check, at their bank. This allows them to redeposit the check at a later time, if available. 

Someone else's check: Cashed or deposited by you
When you cash or deposit a check and there's not enough funds to cover it in the account it's drawn on, this is also considered non-sufficient funds (NSF). When a check is returned for NSF in this manner, the check is generally returned back to you. This allows you to redeposit the check at a later time, if available. In some situations, we'll hold the check and notify you of the returned item. We'll provide you the next steps for check handling.

A substitute check may be returned in lieu of the original check. This check can be negotiated as if it were the original check.