The Egg Hornet appears to be a large Egg Mobile with extra drill attachments. It also features missile launchers at the front. During the game's story, Dr. Eggman uses the Egg Hornet after threatening to take a Chaos Emerald from Sonic and Tails the hard way.
The battle takes place on the round, flat field near Tails' Workshop in Mystic Ruins, with three sets of five Rings floating separately from each other. The Egg Hornet attacks at first by flying far away from the player and starting to fire homing missiles at the player. The player can dodge this attack by constantly moving in different directions. This can be done easily using Sonic's Spin Dash or Tails's Propeller Flying. The player is unable to hit the vehicle without taking damage though.
The second attack of the Egg Hornet is charging into the player with its drill attachments. The Egg Hornet locks on the place where the player is standing and then charges towards the player's position. After Eggman rams the Egg Hornet into the ground, the vehicle gets stuck for couple of seconds, giving the player the change to hit the cockpit with the Spin Jump (or Homing Attack as Sonic). After doing hit once, the Egg Hornet gets up and repeats its pattern. After damaging on the cockpit three times, the Egg Hornet's attachments are destroyed.
The Egg Hornet made a short appearance in the Sonic X anime. According to the eyecatch card, the Egg Hornet is 7 meters tall and weighs 14 tons. Doctor Eggman used this vehicle to steal two Chaos Emeralds from Tails in Mystic Ruins. Sonic then pursues after him and leaps onto the Egg Hornet's side, while trying to stop him. Eggman activates the Egg Hornet's full power and rams into the ground with Sonic being taken down. Tails throws a Ring to Sonic, who destroys the Egg Hornet, though Eggman manages to escape from the explosion.
All three bossvehicles in Sonic Adventure share the code names that are displayed on them. The Egg Hornet name is "EG1" which is below the Egg Mobile's windshield. The placement of the code name is inconsistent, as it can be only seen during the battle with the Egg Hornet, but it is never seen on the Egg Mobile for the rest of the game.
If playing as Sonic, the player can use a glitch to beat the Egg Hornet after it dives into the ground. After it dives into the ground, if the player keeps using the Homing Attack, the Egg Hornet will stay in place and keep taking damage.
Another humorous glitch involves the player getting hit below the Egg Mobile without having any Rings right after Egg Hornet attachments explode. As the player would normally loses a life, the camera direction will instead quickly change to the one with the result screen, except it shows Sonic fainting.