Looks like a walnut or a beechnut

It might be a hickory, like a black hickory, but not sure. I meant butternut not beechnut.

I found one in my yard before. Inside was the remains of the fluffy part of a dandelion I think. I’d like to know for sure as well

I'm excited to see what this is. You have probably already considered this, but the local extension office might have connection to a botanist that could help identify