Captain John "Soap" MacTavish and Sergeant Gary "Roach" Sanderson each use two ice picks in the level "Cliffhanger" to scale their way up the icy mountain to the hidden base this mission takes place in. An ice pick is also used by Captain "Soap" MacTavish to kill an enemy soldier on a snowmobile.
However, in "Cliffhanger", the player will only be able to use them in the beginning. Afterwards, Roach will automatically take out his SilencedACR with Heartbeat Sensor and Red Dot Sight attachments losing the ability to use the ice pick in the process.
If the player doesn't hold on to the wall in "Cliffhanger", on any difficulty, they will fall and die. "Hold on for dear life!" will be shown on the screen instead of the usual random quote. If the player holds on to the ice for too long, it will eventually break up and they will fall. If they are low enough, they will just fall back onto the ledge.
Ice picks act like a dual-wielding melee weapon, but the player is never given a chance to kill anyone with them. The player can, however, still melee with them if they press the attack button while not climbing. Pressing the melee button will swing both at the same time.
"Effective at close-range. Hold Triangle/Y to switch weapon to melee."
The tool, labeled as Cliffhanger (or Icepick in development), is available as a melee weapon in Call of Duty: Modern Warfare Remastered. It was added in the December 13, 2016 update.
It is only available through completing the Cliffhanger bounty collection in the Depot, and is functionally identical to the Knife. However, unlike the Knife, the Cliffhanger can be equipped in a matter similar to that of the Combat Knife featured in previous installments.