Tellurium

Tellurium is an esoteric, tape-based programming language invented in 2016 by m654 with code-golf challenges in mind.

History
Tellurium was originally called Brainfish, and was supposed to be a combination of brainf*ck and Deadfish. It was later renamed Tellurium.

Instructions
Tellurium currently has the following commands:

Turing-completeness
Tellurium is Turing-complete, as Tellurium's commands can mimic brainf*ck's.

Hello, world!
µHello, world!~^

Cat program
i!

Simple calculator
i>i<a!

Python
The original Tellurium interpreter written in Python is available at GitHub here.