Puncture Vine, Bull Thorn
Non-native, invasive, a nuisance weed because the fruits can puncture skin, hide, and rubber.
Difficult to eradicate, much agricultural land was abandoned.
In the 1990s, Two species of weevils were introduced
to eat the plants, which brought the spreading under control.
I'll add a photograph of the fruit when it appears, probably in a few weeks.