anyone?

I am not positive but it could be from the opuntia genus. I have had cholla come up from seed, especially when they do not get a lot of light, look similar to this. If it is opuntia, then there should be small hair like spines as well as the larger spines. If you posted this in the cactus or Arizona gardening forum, they may be able to be more definitive. It has been a few years since I grew any cactus from seed but I recently have started to try to get some of my hedgehog cactus seeds to germinate.