  In quantum information W states are a central class of multipartite entangled
states because of their robustness against noise and use in many quantum
processes. Their generation however remains a demanding task whose difficulty
increases with the number of particles. We report a simple scalable conceptual
scheme where a single particle in an ancilla mode works as entanglement
catalyst of W state for other $N$ separated identical particles. A crucial
novel aspect of the scheme, which exploits basically spatial
indistinguishability, is its universality, being applicable without essential
changes to both bosons and fermions. Our proposal represents a new paradigm
within experimental preparation of many-particle entanglement based on quantum
indistinguishability.
