A plotline could involve a wizard or witch who is on the run from the dark forces in the Harry Potter world. They somehow manage to find refuge on a helicarrier. The helicarrier crew is initially skeptical of their magic but soon realizes they need their help. The 'loo' could be a place where the wizard or witch stores some of their magical items secretly. And as they work together to fight off the common threats, they learn to combine magic and technology in unexpected ways.
Perhaps in the fanfiction, the toilet on the Helicarrier is a portal to Hogwarts. Harry Potter and his friends discover this portal while on a mission to find a lost magical artifact. They end up on the Helicarrier, which is in the middle of a battle. The trio has to use their magic skills to help the Helicarrier crew while also trying to find their way back to Hogwarts through the toilet - portal.
In Lego Batman 2 set in Lego Gotham City, the story revolves around Batman's efforts to keep the city safe. He teams up with Robin and other heroes. They have to deal with the likes of The Joker and his devious plans. There are also side stories involving the other characters in Gotham, and the whole thing is filled with the charm of Lego building and play. For example, there are parts where they have to use Lego gadgets to solve problems and progress through the story.
Titanfall Lego bricks were made by Lego enthusiasts using Lego bricks to make mecha models related to the game Titanfall. These Lego models included the sniper rifle KraberAP, assault rifle R-101C, shotgun Eva-8, smart pistol MK5, Data Knife, and mecha Atlas. These models were exquisitely made, and the degree of detail restoration was very high. It was amazing. Although there were no official Lego models, some Lego enthusiasts and manufacturers had released Lego-compatible models of the Titanfall mech. In addition, some Lego enthusiasts shared their Titan Fall scenes and mecha models made with Lego bricks through videos. These works also received much attention.
Lego Titanfall 2 referred to the mech models built by players using Lego bricks. The details perfectly replicated the mech characters in the game Titanfall 2. These Lego mechs were exquisitely made and could even open the cockpit to place the pilot. The Lego style gave these mechs a unique charm, which was comparable to the mechs in Titanfall 2 on the market. However, the search results didn't provide any information about the specific advantages and disadvantages of Lego Titanfall 2.
Lego and Transformers collaborated to launch a set of Lego bricks for the Transformers. This set contained 1,508 particles, which could highly replicate the details of the Prime's appearance and provide a shapeshifting mode. After assembly, the model had 19 joints, allowing fans to transform it from a robot into a truck, or from a truck back to a robot. This was a set of Lego toys that could be switched between two forms without having to be reassembled, allowing Transformers fans and Lego fans to experience the fun of assembling and switching forms. This Lego Prime set was a tribute to the debut of Transformers and the love of the fans.
The Lego company had launched a set of Lego building blocks, which could transform into a robot or a truck. The set had a total of 1,508 building blocks, and the details of the shape of the Prime were highly restored. This was a product that was loved by Transformers fans and Lego fans, allowing them to experience endless fun in the process of assembling and switching shapes.
I'm not sure if there are many fanfictions directly combining 'Harry Potter', 'Helicarrier' and 'loo' specifically. However, you could start by looking at large fanfiction platforms like FanFiction.net or Archive of Our Own. Search for 'Harry Potter' and then within those results, look for any crossovers or unique concepts that might involve something like a helicarrier in a very loose or creative way. Maybe there's a story where a character from Harry Potter somehow ends up on a helicarrier - like Hermione using her magic to transport herself there in a strange magical experiment gone wrong.
It can walk around in the Lego world. Just like how normal creatures move in our world, the Lego monster can use its Lego legs to stroll through the Lego streets or fields.