Squid is one of the most common species in the world. They also eat pretty much everything they find.
Giant squids are one of the biggest invertebrate in the world. The biggest invertebrate of all is the colossal squid. When the colossal squid is alive it can grow up to meter long.
I'm not sure if this work with all but the colossal squid, has an effect where instead of growing longer it gets fatter. When it dies it gets smaller and deflates basically. So that's why the colossal squid look so big when it is alive.
How Squids Hunt
Squids are very ferocious creatures. They kill everything stands in their way. Some they even eat their own kind to survive but. They are not on top of the food chain, the sperm whale loves to eat squid.
Hope you enjoyed.