Paint cup or something else?

[BadAdze]

Once again my girlfriend is probably showing me up. I am so proud of her. Northwest Missouri river find. Is this a paint cup or something else?

 

[birdpointgriswold]

Once again my girlfriend is probably showing me up. I am so proud of her. Northwest Missouri river find. Is this a paint cup or something else?

<img src="http://www.treasurenet.com/forums/attachment.php?attachmentid=740223"/>

<img src="http://www.treasurenet.com/forums/attachment.php?attachmentid=740224"/>

Pecan cracker!

 

[rock]

I have never found anything like it but it looks natural from my side. I could be wrong though, it wouldnt be the first time.