Brain teaser.
 

Just wanted to throw this one in here. K's ball 4th and 10 from K's 5 yard line. Let's say that K29 is punting from his own end zone. His punt is high and short and hits R30 on the top of his helmet at the K 10 yard line and rebounds on the fly back into K's end zone where K29 catches it and is tackled.

The kick never touched the ground. Safety, score 2 points for R and K free kicks for their 20 yard line.

The force that put the ball back into R's end zone was still the kick by K. Therefore, by rule (don't have my rule books handy), K supplied the force that put the ball into K's end zone.

Now if the kick had been grounded, and then R supplied the force by his muff, etc. that put the ball back into K's endzone then K would be awarded a touchback and have the ball 1st and 10 from their 20 yard line.

Please correct me if I'm wrong but I believe this is the only time that K will not be awarded a new series after a legal scrimmage kick that has been touched by R beyond the expanded neutral zone.

I agree with the play, reasoning, etc. As for the last part, this may be a technicality, but I'll let you decide that: K1's punt is muffed by R beyond the NZ, then bounces back behind the NZ; K2 recovers and advances for a TD. Would that be considered "not being awarded a new series?" That is the only other example I can think of.

Either R30's helmet is made out of flubber, or the ball is. :)

Well, the ball doesn't actually have to make it to the EZ before hitting the ground. R just needs to touch it beyond the NZ and not have any new forces after it does hit the ground. While this play is pretty unlikely I think it is withing the realm of the laws of physics. It is definitely more likely than the famous "strong wind" from NF tests and the Case Book.

Actually Mike, you're technically not correct.
 

REPLY: Back to Mike's original premise...NF 5-1-3f says that <i>"When a scrimmage down ends with the ball <b><u>in the field of play or out-of-bounds between the goal lines</u></b> a new series is awarded to...(f.) The team in possession at the end of the down, if R is the first to touch a scrimmage kick while it is beyond the expanded neutral zone unless the penalty is accepted for a foul which occurred before the kick ended."</i>

In Mike's play, the scrimmage down did <u>not</u> end in the field of play nor OOB between the goal lines.