Lol, I've done the same with a beach ball, too when i was younger!

Just watching it stretch,grow & distort like a balloon & get super tight!

I got carried away & the next thing i knew...POW!

Tried to do the same thing with a little mermaid beach ball i one day found just laying in my front yard...how it got there I'll never know but nobody claimed it when I asked around so i gave it a good home...I was happy until i tried blowing it up...the print on it was nice but that ball was a piece of junk...like trying to blow up a paper bag...I really miss the old stuff...