What type of squash or pumpkin is this?

[Stevechi]

A few of these came up in garden from seeds ....never seen anything like this.plant is just like a zucchini or summer squash

[applestar]

Most likely same scenario as this discussion Subject: Mystery squash identification?

Summer squash are easily bee-crossed with each other as well as same species Cucurbita pepo squashes, pumpkins, and gourds. You need to be aware of this if you save seeds and grow them.

[jal_ut]

Yes, if you are going to grow squash or pumpkins, it is best to buy new seed from a reputable seed exchange. They all freely cross and the bees help them along and if you save seed, next year, you will likely get a mystery plant.