Both long to be taller... MUCH taller

Venom knew that before he'd gotten his powers Peter had been the runt of the litter in every sense of the word. Always looking up at his tormentors. And even now he wasn't exactly a tall fellow, being one of the shorter Avengers.

And Gwen, while not bulled, had always been annoyed that she was a tiny little thing. Needing people to help her reach things, unable to see over certain objects...

So honestly it wasn't a surprise that when Venom looked into Peter and Gwen's dreams they had a similar recurring one, one Venom was able to alter just a touch to bring them together...

In the dream Peter and Gwen were holding hands, enjoying a leisurely stroll. The sun was bright and they were two people in love enjoying the day. The warm light of the sun made their naked flesh feel so wonderful, their huge bare feet padding along as they crushed cards and made craters in the road. Gwen turned, her huge breasts destroying a skyscraper and the two just laughed before Peter suddenly grabbed his titan-size lover and threw her up on Madison Square Garden, her ass caving in the building but also providing the perfect chair for Gwen to sit in as Peter spread her legs...

Both of them woke at the same time with the same thought: Py particles exist... why not give it a try?