Giant Squid is Nightmare's joke weapon in Soulcalibur IV. It can be bought in Character Creation for 12,800 Gold after completing Story Mode with Nightmare. Unlike most joke weapons in SCIV, this one does not have a native skill. As the name indicates, it comically resembles a large squid in appearance, although it is much smaller than an actual giant squid.
In Soulcalibur V, Giant Squid is unlocked at level 53, like the other joke weapons.