The rind is soft if I pierce it with my fingernail kinda like a summer squash.

Whole plant. It 4ft high but would climb higher if it had a higher fence

Can we get a pic please?

There's a couple squashes that climb and are often eaten as tender summer squash, but I don't think any of them are yellow.

Gourd? Don't squash all start out kinda soft at the immature stage?

There are LOTS of vining yellow fruited summer squashes - zucchini, crookneck, eight ball, pattypan - but none that look like that. I'd guess a gourd as well or some sort of garden hybrid. Squash family plants are notoriously promiscuous :-)

Summer squash have tendrils, but they are tiny, and can't support the plant. Hence, they are considered "bush-like" rather than "vining". The stems can be long, however, and you can support them on a trellis, but you need to tie them up. That is, you can tie up stems like vines, but they are not really naturally vining. This mystery squash seems not to be one of those.

Looks like a gourd type perhaps with the shape, bumps, and vining habit. Could be a winter squash type or a cross-breed of some sort too.

It's normal for squashes to have skin that is pierced by a fingernail when young- one of the tests for maturity is when their skin has gotten hard enough that it can't be pierced with a fingernail.

Have you tried one yet?

I'll add my vote to the gourd contingent. Looks like one of the ones I bought last Fall for table decorations.

Gourds I've grown have white blossoms and differently lobed leaves. Those leaves and blooms look like something in the pumpkin family - c. pepo?

Gourd blossoms:

Squashes cross easily, so if you get a volunteer, it can be totally different looking. Immature winter squashes can sometimes be eaten like summer squash.

It looks pretty healthy. I'd try one now and let others mature. Those blossoms are probably pretty tasty too. I make fritters with male winter squash blossoms, since there are always way more than needed. I've also used them sliced/chopped up in dishes like rice pilaf.

Those warty fruits remind me a bit of Hubbard squash.

I have always thought that gourds had white flowers that opened at night?

The summer squash I have grown are usually a bush type. This thing has crazy tendrils, is very bushy and wants to go straight up. I've been whacking it back out of the walkway from the back porch lol.

It has been trying to choke out my potted roses and I have been ripping the tendrils off of it. It has been doing so well so I havent pulled it out. I will probably have to move the roses soon. Then I'm sure it will find its way to the gazebo behind it.

I know there are some climbers like Rampicante zucchini but its long, snake-like and light green.

There's zucchini Tromboncino that climbs but it is long light green and crooknecked.

I did grow Seminole Pumpkins last year but this does not look like them. I didn't grow any summer squash last year because I was too late getting it started and bugs got it.

A few yrs ago I grew lots of Bird House gourds and also a Snake gourd.

Our chickens and pigs have planted some seeds here and there lol. I cant think of anything I have fed them that looked like this.

I didnt buy any decorative squash or pumpkins last Halloween either. I usually do but I didnt last year.

I havent tried it yet. Tonight we are eating ribs & potato salad.

I will have to think of something to do with the mystery squash tomorrow lol. Hmmmm...

Maybe some roasted squash to go with?

I'd sacrifice a small one and cut a piece to try raw first.

It just started fruiting recently so not that many are very big yet. It looks like lots of little tiny ones are starting though.

There's one that is half the size of the biggest one.

I am tempted to tie one to the fence and see how big they get.

This is the largest one so far. This is a 10 0z coffee mug next to it. The rind is soft on it so its not mature yet, so still growing?

Smaller one

Here is how the endsof the tendril/vines look

The squashes/gourds start out golden yellow and have stayed that color so far

FWIW, there is a warty yellow summer squash variety, but it's a crookneck type:

Fairly certain it's a cross and I still think it may have came from a Hubbard or similar.

Can gourds cross with squashes?

I will try one tomorrow and let y'all know if it tastes like a summer squash.

Carol, That is what I thought it was at first but then it never developed a crooked neck. Those are my favorite summer squash btw!! :) I think the yellow crook neck summer squash is a bush.

I was really hoping for a yellow summer squash when it first started growing random..there has never been any veggies in this spot before. I am beginning to think a wild bird dropped it there.

I have a patty pan and Black Beauty Zucchini growing in the veggie garden now and they are just bushy. I looked closely and they have teeny tendrils but nothing to really climb with.