
Baldur's Gate 3 has the soul of a doomsday prepper in the sense that the RPG is always ready for even the most unlikely scenarios, as one player recently demonstrated with a rare Astarion scene most people miss during a typical campaign.
Here's the situation: it's possible that, after you long-rest multiple times in Act 3, vampire spawn will ambush your camp with the hope of returning Astarion to his sadistic master Cazador. And it is also possible that – as Reddit user Soft_Stage_446 explained in a thread – you can become Astarion soon after this, but only if you meet a very specific set of conditions.