What does the Bee symbolise?

Firstly, this bee is not always a bee.

The bee is a clickable bonus. Unlike the food clickable, it moves, and once off the left side, you missed your chance to get it. Clicking it appears to slow it down for a moment, but that's an animated illusion.

• The clickable appears in an area where clicks do not register on the monster of the level. If you're idling, you will remain idling even if you miss to the left or right of it, click directly on it, or click too much and hit the area behind it after it's gone. Only if it randomly activates the clickstorm does it disable your idle status.
• You need to click it many times – 50 – to activate it.
• When activated this clickable can in turn activate any skill except energize and reload. Even if the skill is in cooldown or locked.
• It won't reset the cooldown nor start a cooldown for the activated skill.
• It will show a message about what was activated and the activated skill will be highlighted with a gold border box in the toolbar.

• Since no cooldown is started you could, inadvisedly, manually activate the same skill while it is still active from this clickable. In that case, or if you had just activated that skill before the clickable activated it, the activation time is not additive, it simply stops the old activation and counts as a new activation starting from when it is removed with the last click.

• The skill activated would use the multiplier from energize if you left an energize activated before clicking the bee.

If you have no skills unlocked at all, the skill toolbar will not be drawn and you won't see the golden border around the skill it activated, however the skill will still be active as described above.

While mostly harmless to idle play, it has a higher chance of activating clickstorm, than other skills, this is harmful to idle play, and the only reason to avoid it while idling.

It is a small powerup ("clickable") for non-idle style players. If you click it 50 times, it will activate a random skill without causing it to go on cooldown (or activating it anyway if the chosen skill is already on cooldown).

They seem to be a little rarer than the gold/ruby clickables.

Even if there are some other answers already given I want to clarify it a bit.

The bee is as already stated, a clickable bonus. It will fly from right to left and then disappear if you won't activate it early enough (if it reaches the left side). You need to hit it many times to activate it.

The Bonus can any Bonus from the skill toolbar. Even if the current skill is in cooldown. It won't reset the cooldown or activate it if the bonus is ready for use again.

Beside the info, that it's just for active players, I would prefer to activate it even if your and idle gamer. You can get a lifetime dark ritual with the bee. This will even last if you ascend and permanently give you a 5% bonus (DPS * 1.05) to your DPS. This is a good thing for idle players too, even if you loose your idle bonus for 1 minute.