Link to character's info post: Info post.
Is this a memory Echo? YES
Type of Echo: Memory.
Are you using a Double Echo Token? No
Reason for Echo: Canon recurrence, skeletons where there should not be skeletons. This is Russell's first time seeing a real skeleton up close and 'sleeping' on the ground, rather than plastic models hanging around art or medical locales.
What is returned: Memory of finding his brother sleeping by the Waterfall sentry station, lecturing him, and Sans glancing up at him in a wink.