The Tinkerer (Phineas Mason) is a character appearing in American comic books published by Marvel Comics. The character is usually depicted as an adversary of the superhero Spider-Man and the father of Rick Mason. The character was created by Stan Lee and Steve Ditko, and made his first appearance in The Amazing Spider-Man #2 (May 1963). The Tinkerer is generally depicted as a genius in engineering who is able to create gadgets and other devices from nothing more than spare parts left over from ordinary household appliances. While in his initial appearances he sought to personally eliminate Spider-Man, more recent storylines depict him under the employ of other supervillains, whom he supplies with his gadgets for their personal vendettas against Spider-Man or other heroes.

Since his introduction in comics, the character has been adapted into several other forms of media, such as animated television series and video games. The Tinkerer made his live-action debut in the Marvel Cinematic Universe (MCU) film Spider-Man: Homecoming (2017), portrayed by Michael Chernus. Additionally, a younger female black version of the Tinkerer named Phin Mason appears in Spider-Man: Miles Morales, voiced by Jasmin Savoy Brown, depicted as the sister of Rick Mason and the childhood friend of Miles Morales.

The Tinkerer was created by Stan Lee and Steve Ditko, and made his initial appearance in The Amazing Spider-Man #2 (April 1963), opposing Spider-Man as a villain. It would, however, be several years before he would return, and made his second appearance in The Amazing Spider-Man #160 (September 1976), once again opposing Spider-Man in a losing effort. The Tinkerer would be mentioned in The Amazing Spider-Man #182 (July 1978). This was his first mention in the publication as a supporting side character to the other villains.

Phineas Mason is a brilliant inventor and technician who designs advanced weaponry for criminals and sometimes undertakes crimes of his own. As "the Terrible Tinkerer", he runs an underground fix-it shop disguised as a radio repair shop. On at least one occasion, a potential customer gained the inventor's attention by presenting a transistor radio and telling Mason that "I've got a radio that just can't carry a tune". The Tinkerer's original scheme involved the employment of a team of petty has-been stuntmen and thugs. They specialized in placing bugs into radios and blackmailing state officials and politicians.

The Tinkerer's next encounter with Spider-Man resulted in deploying the Toy, a hi-tech robot that serves as an assistant and lackey. The Toy also helped the Tinkerer escape from his hideout when raided by the police.

Since he is a small business operator who works alone (and arms criminals), the Tinkerer takes precautions to prevent being cheated. For instance, Killer Shrike commissioned Tinkerer to improve his weapon gauntlets. At delivery time, Killer Shrike decided to use the weapons to threaten the inventor and avoid paying. The gauntlets backfired on Killer Shrike due to a failsafe created by Tinkerer and implemented into his products for such situations.

Tinkerer's son Rick Mason is a world-class mercenary for the American government and freelance operative. Despite the two being on opposite sides of the law, father and son remained on good terms and met frequently. Tinkerer even aided Rick from time to time, and once provided his son with information about a coup in South America. After Rick was seemingly killed in action, the grief-stricken father decided to mend his ways while still maintaining links to supervillains to give information he could discreetly pass along.

In the Secret War miniseries, Nick Fury discovered a link between the weaponry of many technology-based villains and the kingdom of Latveria. Tinkerer was revealed to have received a vast portion of his funding and presumably the resources and technology from which he has developed most of his clients' arsenals over the years from Latveria. This was part of an ongoing "terrorist" initiative fostered by Latveria's leader Doctor Doom and prime minister Lucia von Bardas. S.H.I.E.L.D. agents discovered Tinkerer's workshop by using Killer Shrike as a mole. When the agents converged on the workshop, the canny villain detected this. Killer Shrike was struck down by Tinkerer's security systems, and Tinkerer fled to Latveria rather than face justice.