Fusion gives you the opportunity to remove three weaker Bees from your Hive and receive a Gen 1 Egg in their place.  Hatching a Gen 1 Egg results in a Gen 1 male Bee.

Stats, traits, and moods cannot be controlled. They are randomly assigned when Eggs are Hatched, so you won't know the stats of the Bee you receive from Fusion until Hatching is complete. However, Gen 1 Eggs tend to produce stronger Bees than Gen 2 and Gen 3 Eggs.

You can fuse any three male Bees (that are currently activated in your hive) with the exception of Training Bees. Training Bees are not eligible for fusion.

The three fused Bees will be removed from your hive as they are burned (deleted) during the fusion process. Fusion cannot be reversed.

The cost to fuse three Bee is 50 HXD plus the fee required to mint the resulting Gen 1 Egg.

Visit the Bee Lab to use Fusion.

This chart shows you the Egg Hatching Mechanism and how the stats of the resuting Bee is determined: