Factor, 13 bytes

Factor has automatic memory management, but also gives access to some libc functionality:

1 malloc drop

Manually allocates 1 byte of memory, returns it's address, and drops it.

malloc actually registers a copy to keep track of memory leaks adn double frees, but identifying the one you leaked is not an easy task.

If you prefer to make sure you really lose that reference:

1 (malloc) drop

Testing leaks with [ 1 malloc drop ] leaks. says:

| Disposable class | Instances |                    |
| malloc-ptr       | 1         | [ List instances ] |

Testing leaks with [ 1 (malloc) drop ] leaks. says:

| Disposable class | Instances | |

Oh no! Poor factor, it's got Alzheimer now! D: