Contrary to popular belief, helicopters do not belong in the sky. They belong on the ground, in many pieces of exploded shrapnel.
The Helicopter Death Doctor Challenge was a challenge for the game Thing Thing 4 that was released on April 3rd, 2008 and lasted until April 10th, 2008. To get it, the player had to beat level 14 (a helicopters boss, hence the challenge description). Beating the challenge gave the player the replay 1 version of the Healing Salve card.