Bitsquatting registers domains that differ from a legitimate one by a single flipped bit. A bit error in a device's memory — caused by heat, radiation, or faulty hardware — can corrupt one character of a domain as it is processed, sending the request to the bit-flipped variant instead of the real site.
For example, flipping a single bit in one character of acmebank.com produces a neighboring domain whose ASCII code differs by exactly one bit from a real character. Across enough devices and requests, a small but real stream of traffic reaches these domains with no user typo involved.
Bitsquatting is rarer and more opportunistic than typosquatting, but it belongs to the same lookalike-domain permutation space that comprehensive monitoring should cover.