That's an Ibis, TIG-welded Ti alloy.
Most of them are good, this one apparnetly had a bad weld. Too little penetration, or bad prep or argon shielding, we'll never know.

Scary? Well, it's in an extremely noticeable spot, so unless it snapped off from a one-time event (unlikely), the crack probably would give lots of warning, growing slowly at first. Not as insidious as fatigue cracks that grow in a place that you can't see until it's too late.