From RWP Wiki
A Honeycomb is a health unit in the Banjo series.
The Honeycomb unit is the basic health unit in the game, and can be taken away by enemies, environmental hazards or falling too far. Collecting 6 empty honeycomb pieces will add one more honeycomb piece to your health bar. Honeycombs can be found in killed enemies, in beehives, and just out in the open. In the tower part of Grunty's Lair, you can add a "second layer" to your honeycomb pieces by completing a honeycomb puzzle behind a note door. This will double your health, but of course it takes twice as much pieces to refill. The second layer of honeycombs are reddish in color.
The health bar is slightly different, being in a single row instead of the honeycombs fitting together in two rows. Every character you control will have a honeycomb meter, an air meter and a small icon of the chosen character. Honey B is the queen of the honey on the Isle o' Hags and by taking empty honeycombs to her, you increase your health bar for all characters. Whenever you talk to Jamjars, much like Bottles in B-K, they refill your health bar for free.
A honeycomb with an exclamation point on it will start a little game, where the honeycomb meter moves up the health scale, then to the bottom, then up again until time runs out. Click the B button when it's nearest to the top of the meter to get that many honeycombs. Very useful if you need lots of health, fast.
A honeycomb with a question mark will start a game like the ! honeycomb, except the highlighted honeycomb will go randomly across the meter, and how many health honeycombs you get as a result is a matter of luck.
Banjo-Kazooie: Grunty's Revenge
All honeycombs return, but also introduces a new honeycomb. A honeycomb with 2x on it will refill your energy 2 points instead of one.