Flux Constructs are Overworld bosses that appear in Tears of the Kingdom.
Tears of the Kingdom
Flux Constructs are massive Overworld enemies that take on multiple forms. Its body will shape shift into a more humanoid form, a rolling box, as well as a flat plain, which Link can use Ascend to get through. Higher levels of Flux Constructs can also protect their weak spot (a glowing green block) by teleporting it to different places on its body. All of Link's primary abilities are useful during this boss battle.
The first Flux Construct that appears is Flux Construct I, who is located on the Great Sky Island. The Flux Construct II and Flux Construct III are both stronger and can be found elsewhere. The Flux Construct III has the ability to shuffle its core cube around to make it harder for Link to detach it.
In this phase, the Flux Construct takes the form of a walking humanoid. There are three attacks it can perform: a charged up punch(which, if dodged, allows an opportunity for Link to run up its arm), a teleport smash(in which the construct will raise its arms, teleport on top of Link, and slam downwards), and a stomping charge(where the construct will walk towards Link, creating shockwaves with every step). These attacks are simple to avoid and Link can usually just run out of the way. In order to stun the boss in this phase, use Ultrahand to pull the glowing block out of the construct.
Flying Platform Phase
In this phase, the Flux Construct takes the form of a floating horizontal platform. There are two attacks that it can use, one where it flings five blocks out one after another, and another where it hangs five blocks, and then flings them towards Link simultaneously. While the Flux Construct I hovers lower in the air and allows Link to ascend up into it easily, the two stronger variants hover much higher and prevent the use of Ascend. To turn the tables on the construct, use Recall on one of the blocks and climb onto it, allowing Link to get on top of the floating construct and attack the glowing block, or pull it out using Ultrahand.
Rolling Cube Phase
In this phase, the Flux Construct transforms into a cube and rolls around the arena. The stronger variants can also use an attack where they try to smash Link while in this form, and Link will also take damage if he gets crushed by the cube. Use Ultrahand to pull blocks out of the cube to reveal the cube core if it is obstructed by other blocks.