The giant isopod is a deep sea crustacean, a relative of crabs, shrimp and most obviously, woodlice. It looks a lot like a woodlouse out for a swim. A ONE AND A HALF FOOT LONG woodlouse out for a swim. These things get BIG! The effect is strange, we just don't often see such massive compound eyes and chunks of exoskeleton of that size, especially when it looks so similar to something so small. It seems uniquely weird and otherworldly. This impression isn't helped by having 2 pairs of antennae and 4 sets of jaws.
The giant isopod lives on the sea floor, some can be found as deep as 2,000 metres beneath the surface, where temperatures can go down to 4 °C and all around is pitch darkness. Down here, they can scavenge for dead whale, fish or squid, although it is believed they can also predate slow moving creatures such as sponges and sea cucumbers. No matter what you eat, you won't find much of it at the bottom of the deep sea, thus, when food is found, the giant isopod reveals itself to be a terrible greedy guts. They will eat and eat and eat until they find it quite difficult to actually walk away. All in the interest of survival you understand, they're not simply bad dinner party guests. If there is a need, they can go 8 weeks without food... and without dying. They can even roll up into a ball for protection from predators such as sharks, I think we can all agree that getting eaten is seldom a good thing after all.
Baby giant isopods look just like really small giant isopods. I'm afraid I don't know exactly how big that is, but I personally hope it's about the size of a really big woodlouse. It's thought that they have the biggest eggs of any marine vertebrate, which the female keeps safe in a pouch about her person until they hatch. That's great, except that she may lose them all if she eats too much. Greedy, greedy, greedy guts.