The brown button or trap button is a tile that releases the trap to which it is connected, if any, when moved to the lower layer by any object (it is unconditional acting floor) or if it already starts on the lower layer. If the brown button does not have a connected trap, it has no effect when stepped on. More than one brown button can release the same trap, but more than one trap cannot be released by the same button.
Under the pedantic Lynx ruleset and in Chip's Challenge 2, brown buttons are automatically connected to the next clone machine in reading order. In Chip's Challenge 2, brown buttons cannot be wired to clone machines, but pink buttons can.
The brown button is the only button not affected by the Button Smash Glitch in a specific case. Only currently trapped items will fail to be released when the button is "smashed".