Shadow Body.
The vampire can shift into a shadowy humanoid. In this form she is mostly invulnerable, can see in the deepest shadow, or pass through the smallest cracks.
The vampire must spend three Blood Points, and the change takes three turns. He will be immune to physical attacks, but may not physically attack anyone. Fire and Sunlight damage normally, but the difficulty to avoid Roetschreck in those conditions is one higher in this form.
Please note that you are NOT invisible, that if the area is not full of dark and shifting shadows (ie, lit only by unshielded/guttering firelight) you WILL be seen, and you CAN be recognized on a successful wits + alertness vs 8 roll. For those of you who don't have the books, 'successful' (full success) is defined in the White Wolf system as meaning '3 or more successes'. Remember that.