Can someone explain?
Another word for the season of Autumn is Fall.
Thus, the DM is about to make a pun about Fall damage. The player of the bard notices the incoming pun, takes defensive action via casting a counter-pun spell, and thus prevents a table full of groaning and moaning, and possibly even laughter.
Laughter from a pun like this is a rare thing, a charisma check of 19 with disadvantage.
More like charisma save, DC 0
We’re D&D players, we all have a -1 at most
Because no one else is doing it, I’m going to take the hit. Feather Fall in D&D 5e prevents falling damage, not fall damage. Sorry to ruin the pun, but someone had to.
You did not successfully ruin the pun, as it has been made clear it does not live or die by the Ing.
However, you did ruin the mood. I banish you to a lower tier.