This summons an Invisible Stalker. The Stalker will wait until they're given a task and then work tirelessly to achieve it. Once they achieve it or are killed, the spell ends. If they aren't given a task within 3 minutes of arrival, the spell also ends.

They hate long tasks that keep them off their home plane (Plane of Air) and will seek to twist their instructions if kept away from it more than a few hours.

Affliction [58] 
    Advantage [+200%] 
        Jumper (World) [20] 
            Interplanar Only [+0%] 
            Naked [-30%] 
            Special Portal: Only to the caster [-60%] 
    Temporary Transport [+0%] 
    Summons Non-Specific Targets [+0%] 
        Cannot summon a specific invisible stalker 
    World-Spanning Only (Interplanar) [+50%] 
    Cosmic (Required for World-Spanning) [+50%] 
    Cancellation [+10%] 
        Touch or second activation roll to dismiss target 
    Malediction (As Regular Spell) [+100%] 
    Based on Activation Roll [+5%] 
    Resisted by Will [+20%] 
    Extended Duration (Permanent) [+150%] 
        Ends when the Stalker completes their assigned task 
        Or after 3 minutes if they're not given a task 
    Only Affects Invisible Stalkers [-40%] 
    Takes Extra Time 2 [-20%] 
    Magical [-10%] 
    Spell Components [-40%] 
        Must say "invisible stalker" in Latin 
        Must gesture with hands 
        Must burn incense 

• Invisible Stalker.gcs