Deadfish
Deadfish is a dead-simple esolang created by Jonathan Todd Skinner. Four straightforward commands, no conditionals, no loops. It was the second language to be added to Esolang Park simply because I was feeling a bit lazy. The esolangs wiki page is the only resource used for this implementation.
In all honesty, Esolang Park does not do Deadfish justice. Deadfish is designed for writing highly interactive programs, but due to the lack of support for interactive input a lot of Deadfish's power is taken away.