Seed?

Not sure what this is or where it came from, so I'm hoping that my Blip Friends might know.
Smoochi (our Dog) came back from the walk yesterday & I noticed she started limping 200 metres away from home, so I picked her up & carried her home.
Once at home I looked at her paws & found this inbetween her pads on one of her paws.
Looks like some sort of seed head.
Anyone know what it is please?