Sorry for that stupidish question. I invested 2013 in Bitcoin and holding since then. My Coins are on a paper wallet and I don't have much to do with cryptos since then. Everybody is talking about tether these days. I have no idea what that is again. Do I have to do anything with my bitcoins before this tether thing crashes? Or simply hold another few years?
It isn't stupid to ask IMO.
Very briefly:
Tether, as per the FAQ pointed above, is a substitute for USD pegged 1:1.
It's being used to add fiat-like liquidity.
There are worries of over-creation of tether (fractional reserve), along with more complex hypotheses.
If it is a fake, and it pops, there will be some blood and unpleasant consequences on BTC price.
However, bitcoin has lived through worse events (Gox, for example). If one believes in the long-term future of bitcoin, tether shouldn't be able to sway their course of action for the long run.
TL;DR: Just hodl.