The term 'Terrarium Youngster' is a job description for an EFT, which stands for Electronic Funds Transfer. An EFT is a type of electronic payment system that allows money to be transferred from one bank account to another. This type of payment system is commonly used for online purchases, direct deposits, and other types of financial transactions. A Terrarium Youngster is someone who is responsible for managing the electronic funds transfer process. They are responsible for ensuring that all payments are made accurately and on time. They also need to be knowledgeable about the different types of payment systems and be able to troubleshoot any issues that may arise.