In the expansive world of Lego Batman: Legacy of the Dark Knight, a hidden red brick awaits discovery during the "Red Hood Gang" mission. Upon collection, this special item bestows players with the "Toxic Waste" modifier, transforming character costumes into a distinct yellowish hue accented with green details. While often conspicuous, this particular brick's placement requires keen observation and strategic maneuvering to avoid overlooking it amidst the mission's challenges.
Your quest for the red brick commences in the first chapter of the "Red Hood Gang" mission, deep within the ACE Chemicals factory. After infiltrating the main facility, you will eventually enter a large chamber dominated by a central tank and patrolled by Red Hood adversaries. Once the area is secured, proceed to the right side of the room to discover a doorway. This passage leads to a brief corridor. Upon entering, direct your gaze to the right.
Within your line of sight, a glass pipe containing the coveted red brick will be visible through a series of large windows. To reach this area, continue through the corridor and turn right just before the exit door. Here, a small opening at the base of the wall offers a discreet entry point into the pipe room.
To initiate the retrieval of the red brick, it is crucial to switch to Jim Gordon. Employ his specialized foam sprayer to seal the green poisonous liquid leaks within the pipe. This action will create pressure, propelling the red brick to the opposite end of the pipe. Apply additional foam to the second leak, and observe as the red brick is ejected from the pipe room.
Exiting the pipe room can be achieved either by re-using the small opening or, for Batman, by utilizing the Batclaw to open a vent duct above. Regardless of your chosen exit, make your way back to the beginning of the corridor. Here, you will find the red brick on the ground, but it remains inaccessible due to the leaking poisonous liquid. To resolve this hazardous situation, once again switch to Jim Gordon and use his foam sprayer on the pipe. With the area now safe, you can finally claim the red brick and unlock the "Toxic Waste" modifier.