Dragonfly

The Dragonfly is a giant from the Reign of Giants DLC. It appears in Summer and is apparently attracted by Birchnuts. One of its abilities is spitting lava, which it will casually spit on various objects while it is in its calm state in order to produce Ash, which it eats. Once the Dragonfly has consumed enough Ashes, it will stop spitting fire. If attacked or if the player stays too close for too long, it enters an "enraged mode", where it will light everything in its path on fire. During rain, this mode doesn't last as long, and if frozen, the Dragonfly will immediately return to its calm state.

It takes 58 hits with a Spear, 47 hits with a Battle Spear, 20 Blow Darts, 33 hits with a Ham Bat, 47 hits with a Bat Bat, and 30 hits with a Dark Sword to be killed. It drops Scalemail and 8 Meat.

Attack Pattern
In close range, the Dragonfly will do a large area of effect attack after squeaking. If the player wants to hit it without getting hit, there is a 2-hit space between its attacks. After being left alone for a while, the Dragonfly will calm down and revert to its green form. When attacked in the green form, it can chain two of these attacks together in a short span. Attacking with any ranged attack seems to provoke it into using its area attack, making it easier to get away.

It also has a short range swipe, but it is rarely used.

Strategy
One of the easiest ways to deal with any boss in Don't Starve is a Sleep Dart/Pan Flute and Old Bell/9 Gunpowder combination. Not only does the 9 Gunpowder bring the Dragonfly down to 200 health, but you can easily take it down from there with 2 Blow Darts and still get its loot.

20 Blow Darts can make short work of the Dragonfly. Using either a Blow Dart attack or Ice Staff will coax it into stomping giving you time to get away after swinging at it with melee weapons.

The Old Bell can be used twice to finish it off while still obtaining its loot. Treeguards or any type of monster with large amounts of health seem to be able to fight the Dragonfly and deal noticeable damage.

Refrain from luring it to areas with Beefalo or Pigs, as tempting as it may be, as it will simply kill them all in 1-2 attacks.

If you start in spring or even summer and don´t have to resources for the aforementioned strategies, try to bring it to a swamp by either going to a swamp when you hear its growl or by luring it there. Use the hostile tentacles and or the fishmen there. Ideally you want to put down some ash close to tentacles, this will make him come there. Everytime he kills any hostile monster, he will be reset to a calm state, rinse and repeat the process untill he simply drops dead.

Trivia

 * The name and appearance of the Dragonfly is a tongue-in-cheek portmanteau of the words "dragon" and "fly".
 * When enraged it stomps, then causes fire to fly around it.
 * It is attracted by Birchnuts but, instead of eating it, it will spit lava at it. This is possibly a reference to how flies spit out their digestive juices onto their food before sucking them up.

Bugs

 * After death buzzing can still be heard at its death place.
 * When killed while it is in its enraged state, it has a chance to die in its calm state or its enraged state.
 * When you hit the Dragonfly right before he eats ashes he will be bugged, standing in one place untill the ashes dissapear.

Gallery
Драконья Муха