Spectral Lynx can regenerate even if it isn’t in combat, it’s already tapped, or it’s undamaged.

You can activate the regeneration ability even if Spectral Lynx isn’t at risk of being destroyed.

Activating the ability creates a replacement effect that acts like a shield, replacing the next time Spectral Lynx would be destroyed that turn. This shield works against effects that try to destroy Spectral Lynx or lethal damage that would be dealt to Spectral Lynx.