Tako is Octopus sushi. It is poached and a bit chewier that most other sushi, except perhaps Giant Clam, but it is a hardy bite. The only thing to look out for is that sometimes, depending on the way that the octopus is cooked, it can be chewy.
It's still worth the adventure but it is something that a novice sushi eater should stay clear from until they are ready for a hardier bite. The tentacles are what is used to lay over this rice. Since it is a bit still, a piece of nori is often used to hold the octopus atop the rice.