There are many plants with thorns on their leaves and stems, so it's difficult to pinpoint a specific "weed" without more information.

To help me identify the plant you're thinking of, please tell me:

* Where did you see this plant? (e.g., garden, field, forest, roadside)

* What does the plant look like overall? (e.g., height, shape, color of flowers)

* Are there any other distinctive features? (e.g., specific leaf shape, smell)

Once I have more information, I can narrow down the possibilities and help you identify the weed with thorns.