The Recordasphere was a small flying globe that could communicate and record Dr. Banner's research. For a while the Recordasphere was Banner's sole companion in Northwind Observatory, with Banner having given it an intelligence so that it could be so.
The Recordasphere developed some sentience and became emotionally attached to Banner, jealous of those who entered their solitude- It even came to believe that it loved Banner. It was later destroyed while trying to protect him from the Abomination.
You never knew why Banner would ever try to rebuild it.