And the winner is...

...this thing.

I have no idea what it's called.
The boy got it for £1 at the car boot sale.

First of all, it got a scrubbing, with bleach of course; can't be too careful.
Then we tried it out. It has a big button on the front, as you can see. When you pressed it, nothing happened. So I put new batteries in it; 4x AA cells it took.

Then I pressed the button to see what happened. Big mistake.

It makes a lot of noise, I couldn't find the volume.
I couldn't switch it off, it keeps going, if you wiggle the ears it makes more noise, if you flick his quiff, it makes yet more noise. It goes on and on.

I held the button in and it stopped, thankfully. Phew.
Then after about thirty seconds it started up on its own.

So yes, the winner of quite possibly the most annoying toy in the world.