It seems to be a Solanum species. It doesn't match perfectly with any Solanum species native to Texas, but there are a few uncommon species, and the more common Buffalo Bur, Solanum rostratum, that have similar leaf shapes. It's common for Solanum species to hybridize and that may be the case here. I suggest getting photos of it in flower, and we might get a better idea of the parent species. I haven't checked out any of these hybrids yet. Got nowhere with Ambrosia, Artemisia and Euphorbiaceae.

I felt Solanum too but couldn't find a match.