Tiyanki

The spaceborne lifeforms - which we call "Tiyanki" - are docile creatures. Capable of accessing some lower dimension of subspace, they roam from system to system with remarkable ease. They graze on gases common to the upper layers of many gas giants. It is highly unlikely, to say the least, that this is their only food source, but intake of other nutrients has yet to be observed. They will not attack unless provoked. They can safely be ignored.

The command below will trigger the "Tiyanki" event in Stellaris:

When this event fires, you can choose between these 4 options:

• Venerable.
• Hunting them would be a net loss anyway.
  Available only if Requires ethic: Gestalt Consciousness; Must not have civic: Exploration Protocols.
• Docile spaceborne cataloged!
  Available only if Requires civic: Exploration Protocols.
• Very fascinating.

Stellaris events fire in chains — one event leads to the next. Here is how Tiyanki (first_contact_critters.15) connects.