Source: Spelljammer: Adventures in Space - Astral Adventurer's Guide
5th-Level Transmutation
Casting Time:
1 action
Range:
Touch
Components:
V, S, M (a crystal rod worth at least 5000 gp, which the spell consumes)
Duration:
Instantaneous
Holding the rod used in the casting of the spell, you touch a Large or smaller chair that is unoccupied. The rod disappears, and the chair is transformed into a Spelljamming Helm .