Squid were a species of cephalopod native to Earth.
The Doctor had some encounters with giant squid. (PROSE: Peacemaker, TV: The Power of Kroll)
Squid was among the food eaten by Shockeye and the Second Doctor, partially converted into an Androgum, on Las Cadenas, a Spanish restaurant, during the year 1987. (TV: The Two Doctors)
When Fu Peng invited the Third Doctor to dinner, he told him they were having dried squid and stewed jellyfish. (TV: The Mind of Evil)
Lin thought that Dalek mutants, such as the one she encountered at a dig site beneath Sheffield Town Hall, looked like giant squids. (TV: Resolution) When the Tenth Doctor was aiding the Dalek Prime Strategist against the Hond, he commented on the Daleks' true form being "a bit squiddy", and that that had led him to conclude that the Daleks were swimmers. (COMIC: Defender of the Daleks)