Songfacts®:

• After their 2006 album 10,000 Days, it was another 13 years before Tool released new material - mainly because it was nearly impossible to coordinate their schedules with all the side projects they took on. On August 7, 2019, they delivered "Fear Inoculum," the title track to their fifth album.
  
  Running 10:22, it's a slow build, with layers of sounds emerging until the full instrumentation kicks in around the 1:40 mark. About 20 seconds later, Maynard James Keenan's vocals come in, with the first line:
  
  Immunity long overdue
  
  The lyric is typically enigmatic and open to interpretation, which is the way Keenan likes it: he feels songs are subjective, and never gives details as to their meanings. Speaking with Revolver, he explained that the album deals with "wisdom through age, through experience."
  
  In biology, an inoculum is a culture made from bacteria for the purpose of creating a vaccine (inoculation). "Fear Inoculum" could thus be seen as working to create an immunity or defense against fear. The next line is also a biology metaphor:
  
  Contagion I exhale you
  
  Keenan goes on to address "The Deceiver" who has brought fear into his life. He stands up to and expels his adversary; in doing so he becomes immune to the venom in The Deceiver's words. At the end of the song, The Deceiver is vanquished:
  
  I see you running
  Deceiver chased away
  A long time coming
• On the song's release, the Internet was swamped with suggestions as to the identity of The Deceiver. Is he a specific person or group of people? Or is it the fear within the mind of Keenan? Keenan offered a "broad stroke" in his Revolver interview: "It would be embracing where we are right now, acknowledging where we've come from and some of the things we've grown through."
• Keenan uses yet another SAT word later in the song:
  
  My own mitosis
  Growing through delusion from mania
  
  Mitosis is cell division, another biology term. This could be Keenan resisting his enemies (internal or otherwise) by creating different personas or compartmentalizing his thoughts. There are many possible interpretations here.
• The number seven came up throughout the album: It has seven tracks (on the physical version), and a lot of polyrhythms in seven-times like 7/4 or 7/3 (septuple meter). While working up the songs, guitarist Adam Jones noticed that many of the riffs he and bass player Justin Chancellor came up with were in sevens. Keenan revealed that he had a concept in mind based on the number seven, and Alex Grey, who did the album art, also had something in mind for the seven theme.
• The song entered the Billboard Hot 100 at #93, becoming Tool's first entry on the US singles chart since "Schism," which peaked at #67 in 2001.
• At 10 minutes and 22 seconds, "Fear Innoculum" became the longest song in the history of the Billboard Hot 100 singles chart. The record had previously been held by David Bowie's "Blackstar," which has a running time of 9 minutes 57 seconds.
  
  It held the record until André 3000's 12:20-running track "I Swear, I Really Wanted to Make a 'Rap' Album but This Is Literally the Way the Wind Blew Me This Time" entered the chart dated December 2, 2023, at #90.