"This big blue dude digs the simple things in life - Dark Elixir drinks and throwing rocks. His massive boulders bounce off their targets and hit again behind it for a double strike!"
Level 1 & 2
Level 3
Level 4
Summary
The Bowler is a troop which throws a large boulder that bounces; dealing splash damage on the initial bounce and dealing splash damage again when it lands.
The Bowler is the first ground troop unlocked that can damage multiple targets in a straight line.
The Bowler's boulder will only roll far enough to hit two targets.
Bowlers have no preferred target when attacking; they will simply attack the closest building. However, once they become aware of enemy Clan Castletroops, Heroes, or Skeleton Trap skeletons (either by being attacked themselves or by being near another friendly troop under attack), they will leave their previously targeted building and instead engage the enemy troops. Once all of the nearby enemy troops are defeated, the Bowlers will proceed to attack the nearest structure.
Offensive Strategy
The Bowler doesn't have a lot of hitpoints, so it can be easily destroyed when not protected. Be sure it is behind tanks like Golems or Giants.
Using many Bowlers can be a very strong strategy, as they can take out multiple buildings quickly. They are expensive dark elixir units, second only to the Witch in cost per housing space, but this can be overcome by farming Dark Elixir.
The Bowler can be a great unit for funneling due to their ability to hit 2 structures with one attack. This allows better funneling compared to using Wizards. However, they take up more housing space.
Defensive Strategy
The Eagle Artillery can deal great damage to multiple Bowlers at once. Two shots from a volley will wipe out a whole group of Bowlers.
Spreading out your defenses will make it so that the Bowlers cannot hit all of them at once.
Isolate your Town Hall from other buildings so the Bowlers cannot hit it as part of their boulders' second bounces.
Upgrade Differences
Initially, the Bowler is a blue muscular humanoid creature that wears a loincloth around his waist bound to him with rope and carries a large boulder in the shape of a bowling ball. He has pointed ears and red, sunken eyes. His hands and feet resemble those of a Giant. He also has a yellow band on both arms.
At level 3, the Bowler becomes slightly darker, and his boulder gains pink, elixir colored crystals sticking out of it, similar to the level 5 Golem.
At level 4, the boulder's crystals turn reddish-orange.
Trivia
You can have a maximum of 46 Bowlers at one time in a complete set of fully upgraded Army Camps. This number increases to 52 if you include the 6 that can fit into a fully upgraded Clan Castle. On the battlefield, you can clone an additional 15 Bowlers with three fully upgraded Clone Spells.
When clicking on the Army Camp, the Bowler turns away from the screen, same as the Lava Hound does.
The Bowler's death sound is not unique. It shares a death sound with the Wizard.
In May 4th 2016 update, the Bowler's first attack starts faster, similar to the Valkyrie buffs.
Part of the May 4th 2016 update, the Bowler's training time was decreased from 8 minutes to 5 minutes.
The May 24th 2016 update reduced the Bowler's housing space from 8 to 6.
The Bowler was originally a troop idea for Clash Royale, but being scrapped, it was transfered to Clash of Clans.
Ultimately, the Bowler was added in one of Clash Royale's updates.
Also, the description in Clash Royale is similar to the one in Clash of Clans.
