Once per session a player may, upon their character taking damage from any source or failing a saving throw, choose to transfer the damage or effect of the failed saving throw to the character of the player who was the last to show up for the session, was unreasonably late, and thereby held up the scheduled start of the game; exceptions may be made for players who responsibly inform the group that they will be late due to reasonable reasons such a work or school (but not hangovers and the like) at the DM's discretion.
Bob's Fighting-Man falls into a 30' foot deep pit; the DM informs Bob that his character takes 15 points of damage.
Bob chooses to take adavantage of "Latecomers Shall Be Splintered" and transfers the damage to Harry's Magic-User as Harry showed up an hour-and-a-half later than the other players due to being at the beach.
The DM states "As Bob's fighting man tumbles into the pit he flails his arms around trying to grab a handhold and instead grabs the robe of Harry's Magic-User pulling into the pit as well. As the two tumble down the shaft somehow Harry's Magic-User ends up beneath Bob's Fighting-Man and his body cushions the imapact upon the Fighting-Man ameliorating the damage. Also Harry's Magic-User is now dead."
See also "When You Arrive" Houserule