The Drillerdroid is basically a duplicate of the regular Tunnelbot. An orange and gray robot, it has a roundish central body with a pair of long piston drills on each side. Unlike the regular Tunnelbots however, the Drillerdroid's central body has spikes on the top and two vertical lights up front instead of just one. Also, its whole body is covered almost entirely in thick metal armor.
When Sonic, Tails and Knuckles got into the depths of Lava Reef Zone, the Drillerdroid ambushed them and tried to take them down. However, Sonic and co. tricked the robot into burning off its own armor with magma, allowing them to take it down and proceed deeper into the Zone.
Powers and abilities
The Drillerdroid possesses powerful drills that can tunnel through rock with ease, and the armor it wears makes it virtually impervious to harm. Additionally, its internal components are incredibly heat resistant, allowing them to withstand splashes of magma without suffering more than some minor incandescence.
While the Drillerdroid's internal components are heat-proof, its armor is not, meaning it cannot withstand the magma-leveled temperatures its innards can resist without taking damage. Repeated exposure will eventually cause the armor to fall off.
The boss makes its entrance by attempting to land in the player's co-ordinates. Upon landing, it will drill into the terrain, causing rocks and harmful stalactites to rain from the ceiling that the player must avoid. The machine will end up drilling too far and increase the volcano's pressure, causing lava to erupt from where it is drilling and damaging its armor. The boss will then jump in the air to repeat its attack.
The armor is impenetrable to the player's attacks, so the player must goad the machine into causing as many eruptions as possible to destroy the armor. After being damaged by lava a second time, the central body's armor will be destroyed, exposing the boss's weak point in that area, and a third eruption will fully destroy the armor on its drills, allowing the player to go to town on it.
If the boss lands in a place it has already drilled in, it will instead jump up and down and cause a giant spike ball to fall onto the arena. If that ball lands where the machine has already drilled, it will destroy the wooden floor, revealing the lava below it and reducing how much safe ground the player has. The boss will not land anywhere where there is no safe footing. A total of nine hits from both the lava and the player will destroy the machine and make the lava cool. The player can then touch the Goal Plate that falls down from above and finish the Act.
The Drillerdroid's drilling attack that causes harmful stalactites to fall from the ceiling is similar to that of the Drill Eggman II from Sonic the Hedgehog 2 except the former does not tunnel into the ceiling to do this.