Ace to five single draw used to often be played with a kill, but the kill wasn't implemented like it is now in Holdem or Omaha.
(This is a five card draw variant, so each player is dealt give cards.) After the last player receives his second card, the dealer pauses for about two seconds during which any player can declare "Kill", regardless of position. The first player to declare a kill them posts a live bet equal to double the big blind. After the remaining cards are dealt, the killer acts last unless the pot is raised.
This method allows a player to raise the stakes after seeing two cards (usually something like bug-ace or ace-duece, but bluff kills are not unheard of at snug tables.)