Sentry Gun (BTD5)

"Creates temporary sentry guns and deploys them nearby."

- Official Bloons TD Battles Mobile description.

Sentry Gun is the first upgrade of path 1 for the Monkey Engineer in Bloons TD 5 Deluxe, Bloons TD 5 Mobile, Bloons Monkey City and Bloons TD Battles Mobile. It allows the engineer to create temporary sentry guns within its range. The Sentry Guns shoot nails which can pop 2 bloons each. One Sentry is deployed every 10 seconds and lasts for 25 seconds. Up to 3 sentries can be active at any given time, without additional upgrades or attack speed buffs to the engineer himself.

This is a very useful upgrade for the early rounds as it acts like several Dart Monkeys all attacking at once.

Tips

 * Deployed Sentry Guns can be selected to change their target priority or sell for $0 to give space for another tower to be placed. Sentries do not occupy footprint space for other towers in Bloons TD Battles Mobile.
 * In the case of BTD5 Deluxe, Bloons Monkey City Flash and BTD6, Sentries' target priority is determined by the Engineer who has spawned them. In BTD5/Battles/Monkey City Mobile, however, Sentries default to First no matter what target priority the Engineer has.
 * They are effective on daily challenges and special missions where the amount of towers is limited, as they do not affect the total tower count.

Trivia

 * If the Engineer is upgraded to Sprockets, any new sentries spawned will have the name "SentrySprockets" on non-mobile versions. These sentries are not affected by Monkey Knowledge in BMC Flash.
 * The Sentries actually might be based off of the Sentry Turret from Valve's Team Fortress 2.
 * The BMC Mobile sentry is missing the  line of code it has in BTD5 and Battles, causing the sentries to spawn anywhere, including on the track, water and unplaceable spots.
 * When a sentry runs out of time, it explodes. The explosion is visually the same as the Splodey Darts one from BTD5.
 * If the engineer is sold in the BTD5 Mobile generation games, all of their sentries disappear instantly.