Monster Plants is a Furni category. They are similar to pets. Each habbo received 1 free seed when the plants were new to habbo. Each plant seed in stores cost 10 credits for 1 seed and 20 credits for 4 seeds. There is no guarantee that you will get a set one once you have bought the seed. Once the seed has been planted/placed in your room it can no longer be traded or sold in the marketplace.