I've got a question regarding Ethereum in general.

Let's say ETH falls apart with it's price.
How does it affect coins which are based on Ethereum? Do they also take some damage or something?
How they're connected with each other if at all?

Another thing is - I've read somewhere that ETH founder (Vitalik Buterin) can wipe all of your ETH with one command or something like that. Is it some meme or is it actually true?