The HoverDoc is a curious bug-like object (apparently some sort of life-form) that follows around Creatures it is dropped upon.
It has an accompanying medical device, the Creature Care Kit. The Creature Care Kit appears as a slide out panel when the HoverDoc is locked on to a Creature. It indicates a Creature's drives and most pressing needs (hunger, crowdedness, etc), as well as details of bacterial infection (with the option of a remedial spray), poisons (with recommended treatments) and fertility (with a pregnancy monitor).
Windows Hint: Press CTRL+SHIFT+H in DS to go to the HoverDoc. Be careful, if the hand is holding the HoverDoc, or it is in the inventory, a new HoverDoc will appear!