As a student many years ago I learned of a paradox of something that is almost a certainty, while at the same time being highly improbable.
For example, if you flip 10 coins the chances of all being heads is very slim. However, if you have an entire Superdome full of people perform the experiment, someone will have an all-heads result.
I thought this paradox has a name but possibly I'm not remembering it correctly or I'm mistaken because I've been googling to no avail...
I believe you are referring to some version of the Infinite Monkey Theorem.