I believe this is a bur cucumber, in the genus Sicyos, possibly Sicyos angulatus. It's similar to Wild Cucumber, Echinocystis lobata, but that plant is easily differentiated by the degree of indentation of the leaf lobes and the fruits. Wild cucumber has deeply lobed leaves and inflated fruits, while bur cucumber has broad, shallowly lobed leaves and the fruit is much smaller and not inflated. Most of the distribution maps do not show this plant in the PNW, but I still believe it's one of the Bur Cucumbers. https://www.britannica.com/plant/bur-cucumber

However, you can do some homework. How many seeds do your little fruits contain? Sicyos have one seed, and wild cucumber has four large flat black or brown seeds. Let me know, okay? That will help me to identify it the next time I see it!