That's called a Forstner bit, and it's not supposed to be in two parts.
We've been working on a custom conference table with a smooth hickory top. The shop has smelled of freshly sawn hickory for the past few days as a result - and you may have seen the plan for some of the drops from this and other projects for holiday gifts from us.
Everything was going well and we were making good progress, and then that single point of failure caught us. The 3-3/4" forstner bit snapped off at the shank.
For those of you who don't know, a 3-3/4" is not your typical "run down to the hardware and get a new one" sort of item.
We've got a new one and backup on order so we can get done.
In the meantime, we've got plenty of other projects to keep us busy.