Stellar companions—whether transient flybys or long-term binaries—can dramatically alter the evolution of protoplanetary

discs. In this talk, we explore how such interactions trigger episodic accretion, drive disc misalignments, and reshape the

conditions for planet formation. We highlight the role of stellar flybys in producing eruptive events and warped circumsecondary

discs, and extend the discussion to circumbinary and circumtriple discs, where ongoing dynamical interactions can warp, tear,

or realign discs over time. Using recent simulations and observational case studies, we examine whether stellar multiplicity hinders

or helps the planet formation process—and why it might be both.