Is this a weed?

I planted some plants i've never grown before now im not sure what is what and i think this is a weed. It started right where i planted my cantaloupe and now its everywhere! Please tell me its not a weed! but it probably is ughhh..thank you all for the help!

 

Looks like Tribulus terrestris... it is one of my favorite weeds! :)

 

wow thanks! so those are the ones that make those horrible goat heads oh gosh im always getting poked by those while im working in the garden.