If QI says it’s ok then it’s ok by me.
Octupuses or Octopodes
The plural of octopus is ‘octopuses’, not ‘octopi’ - if you were being pedantic you’d have to opt for ‘octopodes’ as the etymology of the word is from the Greek okto (eight) and pous (foot) not from any Latin word which might have a plural ending in -i. If the word were Latin, it would be octopes (‘eight-foot’) and the plural octopedes, analogous to centipedes and millipedes.
