Xbox is the first Microsoft console. It released in 2001 and 2002. There are two versions:
The startup: We see a green blobby circle formed in a green and black laboratory. It keeps moving and moving, but everything zooms out in green light and we see a large green, pointy X. Below it is "XBOX", also in green. In a few seconds, the Microsoft byline is seen.
The DVD version: An alternative version can be seen if an XBOX game is inserted into a DVD player (or any CD drive or gaming system that plays DVDs, like the PS2 for example). We see an exploding green flash with green dots and they all form a green bubble circle. It zooms in when we see bacteria-like things, and then green flash zooms in the Xbox logo without the "X". It shines and two lines make it black and turns green again, and in a few seconds, it explodes and makes rock music.
Scare Stuff Edit
Minimal for the original startup, due to the green blob being formed.
High to nightmare for the DVD version. First-time viewers and unsuspecting viewers will definitely be startled by the explosion and loud rock music, especially the latter if they were expecting the original variant instead. The scare factor is lower for people who are used to it. Some people can even end up liking this one for it's great animation and music.