Is it possable to have jellyfish and lobsters and such as pets (no troll+)?

It is possible to have either one in an aquarium. There are many species of both jellyfish and lobsters and they would require different types of tanks and equipment but some can be kept. The easiest jellyfish to keep are the upside down jellyfish, cassiopea species. But they just sit on the bottom of the tank so they would be quite boring to watch. If you are thing about the more "traditional" types of jellyfish, then they can be kept but they require a special aquarium. Many public aquariums have jellyfish displays and they even make tanks for private aquariums. Jellyfish tanks are either sperical or cylindrical because jellyfish float with the current and in a typical rectangular tank they would get stuck in the corner and injure themselves and die. Jellyfish feed on small fish or other small planktonic critters. Jellyfish tanks are expensive and are usually recommended for experienced keepers. Now as for the lobsters, again there are many types. Some are common in the saltwater hobby. The purple lobster or the debelus lobster are smaller but very pretty colored. If you mean the types of lobster that people eat, they can also be kept. These types need an aquarium that is cooler than a typical salt tank so a chiller would be required. In either case, there is no problem with keeping either of these animals. Heck you could go to red lobster or a supermarket and but a live lobster. Just tell them you don't want it cooked and take it home with you. If you are serious about this, let me know and I can design the tank for you. Just so you know, a wall sized display tank can be an amazing feature in your house, but it wouldn't be cheap.