Expanded from a six-minute short, Anna Zlokovic’s unsatisfying horror comedy packages its heroine’s low self esteem as a mutant growth with a mind of its own — treating it a not-uncommon phenomenon.

Anxiety is a monster. No, like literally, at least in the world of director Anna Zlokovic‘s feature film debut Appendange, which had its world premiere at this year’s SXSW Film and TV Festival.

The “evil twin” school of psychological metaphor has been a frequent device in horror fiction, and its familiarity does not much benefit the very literal-minded “Appendage.” Writer-director Anna ...