Zeus

A development tool for the Creatures series, written in Delphi and created by Fuzzie. It was never completed - development stopped in mid-2000 when Fuzzie left the community.

Uncompleted portions included a sprite viewer/editor which supported .spr and .s16 files, a catalogue file editor, a BLK file viewer/creator (which doesn't work properly under Windows XP, unfortunately), a CAOS 'command line' tool, a genome editor, a syntax-aware CAOS editor, a room editor and a PRAY compiler/decompiler.

You can download the final beta version, Beta 14a, from an archive of Creatures Mainframe.

Are you looking for the Zeus (mutation)?