Short-Lived is a difficult Special Mission in BTD5. It is unlocked at Rank 60 (40 in Bloons TD 5 iOS) to play it, making it the final Special Mission unlocked. 1,000 and 100 are awarded upon completion. The player has to beat Monkey Lane, Medium - but towers will only last 10 rounds. The money reward for completing a round is increased to 299 plus the round number
This has only been tested in BTD5 iOS so far, but the player can save and exit the game, resume the game, and every tower's "levels remaining counter" (located where the sell button would normally be) is reset to 10.
Banana Investments Advisories disappear before the interest for the 10th round is being paid. However, the price of $15,200 without Path 1 upgrades is still less than the maximum earnings of $21,995. To achieve maximum earnings collect the balance after 8 rounds as well as during the 10th round.
Saving up money is a good choice, so the player could buy towers that have disappeared again.
The Dart Training Facility is a good choice for this Special Mission, because the player can save up money with a free Dart Monkey at the start, and every time it disappears, you get another one.
The best time to beat this mission is when double Monkey Money is in effect as the player gets 2000.
There is a bug on the iOS version that if the player exits and then load the save, every Tower will have their lifespans reset to 10 rounds again, making the difficulty of this Special Mission considerably easy, as long as the player knows the current lifespans of Towers.
This means that getting Monkey Money in these versions will not become that difficult.
This does not work as it is patched on version 1.6.
In Bloons Tower Defense 5 HD, the player can sell a tower before it disappears, but it doesn't show the countdown, so it's difficult to tell which round to sell it. Also, it doesn't give 299+round end reward, which makes the special even more difficult.