The basic shell is pretty rigid, but everything around it can be changed and tuned to make the deck play the way that you want it to
Spiders tend to be mono-green cards and usually have reach, although the scope of spider creatures has expanded significantly with the release of Marvel's Spider-Man
The game is purposefully complex but also made more fun because each card is unique, and all can change the elements and directions, or essentially the rules, of the play
This isnt the worst ability in the world, but it still takes so much setup
You can discard anything you want to this, which opens things up enormously
Yes, there's people crazy enough to fill out an entire deck with Krakens, Leviathans, Octopuses, and Serpents, slapping a commander like Thassa, God of the Sea, Slinn Voda, the Rising Deep, or (my favorite!) Arixmethes, Slumbering Isle, and then smashing face with giant sea monsters