Oppo Rancisis is a Thisspiasian Jedi Master and High Council member, introduced in The Phantom Menace (1999), where Jerome Blake performs him. The long body, the beard and the coiled tail make him the most alien silhouette in the chamber and, inevitably, one of the least used.
Legends material develops him as a strategist — the Council's specialist in military theory, which becomes relevant the moment the Republic acquires an army — and gives him a royal Thisspiasian background he renounced. Current canon has kept the design and almost none of the biography, so the honest answer to most questions about him is that they were answered in the Expanded Universe and have not been re-answered since.
Catalogue entry. This figure has a verified record here rather than a full write-up — the encyclopedia labels its own depth instead of padding it.