Lego Masters narrows down finalists after high-stakes ball contraption challenge

Lego Masters aired its semifinal episode on July 21, 2025, on FOX. With just one spot left in the finale, the remaining teams faced a complex challenge that tested both creativity and engineering: building a Great Ball Contraption (GBC). Their builds had to transport a LEGO ball from one team’s build to the next, ultimately completing a continuous circuit from start to finish.

The catch was each section needed to tell a story and include functional movement powered by motors, gears, and carefully-timed mechanisms.

Hosted by Will Arnett, the episode featured guidance and judging from Brickmasters Amy Corbett and Jamie Berard.

As the challenge began, the teams focused on making their ball contraptions both stable and imaginative, with themes ranging from fairy tales to chaotic kitchen adventures.

Some teams ran into mechanical issues, while others struggled with timing and structural integrity. As the clock ran out, the judges conducted the crucial ball test to see if each team’s contraption could carry the ball smoothly across all builds.

After evaluating each one’s pros and cons, two teams advanced to the finale, while one was eliminated in a close decision.

Ball trouble and timing issues challenge semifinal teams in Lego Masters

 

 

 

 

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Throughout the challenge, teams encountered various technical issues. Sage and Ian created a fairy tale-inspired build, but ran into trouble when their ball wouldn’t run smoothly.

Ian was heard saying that they were in a jam during testing, though the team managed to fix the problem before time ran out.

Ben and Michael, who designed a spaghetti-and-meatball themed contraption, faced complications with their gear mechanism and had no time to replace it.

Meanwhile, Corey and Rebecca focused on a hairbrush-themed build but added bumpers midway through to manage their ball’s speed. Despite the adjustments, their structure began falling apart in the final stretch.

Anthony and Joe’s concept centered around a kid escaping from his mom at an amusement park. Their story showed a ball following the child through a series of scenes representing forbidden fun.

Although they encountered early testing issues, they managed to stabilize the mechanics in time for judging.

The final ball test revealed glitches in multiple builds. Sage and Ian experienced a minor hiccup, followed by similar issues for Ben and Michael and Corey and Rebecca.

After weighing all results, Amy and Jamie confirmed Anthony and Joe as the first finalists, followed by Sage and Ian.

Elimination leaves two teams heading to the finale of Lego Masters

As the ball tests concluded in Lego Masters, the judges shared detailed feedback on each build. Amy pointed out the strength of Anthony and Joe’s story and the consistency in their mechanics.

Jamie said that it felt like a complete journey during his critique. Sage and Ian also received praise for turning their early problem into a working solution and blending storytelling with structure.

Ben and Michael’s build was fun and had a light-hearted story, but problems with the gears hurt how well it worked. Corey and Rebecca’s idea stood out, but their build started to fall apart and the ball didn’t move smoothly, which lowered their score.

Will Arnett, who watched everything with the judges, pointed out how even small problems could throw off the whole build.

In the end, Corey and Rebecca were sent home. Ben and Michael stayed in the competition by a small margin. Now, Anthony and Joe, along with Sage and Ian, are moving on to the grand finale.

In the final challenge, they will be able to build anything they want for one last chance to win the Lego Masters title.

The finale airs next week and will determine the Season 5 winners of Lego Masters.

Stay tuned for more updates.