Randomly interrupting a conversation with a complete random lie to try to convince as many people in the room that it is true.
If you detect an Untrue Fact you reply saying "Untrue Fact yeah?"
If you reply saying something like "seriously mate?" your a fucking idiot.
Here lads did you know in 2003 Italy was the first country in the world to successfully clone a horse that is capable of understanding basic algebra?
No "Untrue Fact" you dick!