A moment on special teams in which the defense manages to deflect a punt attempt by the opposing punter, recover the blocked punt cleanly, and run it into their end zone without being stopped by an offensive player. Like any touchdown, a blocked punt touchdown counts as six points and awards an extra point attempt to the team. Blocked punt touchdowns are big game changers, since the defense scores points directly without the offense having to receive the punt or move the football.
A blocked punt is a big momentum shift in any game, and being able to return it for a touchdown can be huge for any defense. The two main reasons for this is that it eliminates the field position change that a good punt would have created, and it immediately adds points to the team's score without the offense having to run a single play. Blocked punt touchdowns most often occur when a play breaks through the middle of the line and gets enough of the ball to block it back behind the punter and collect it with their momentum going towards the end zone.