Serpentine is one of the most recurring Bosses in Freedom Planet, being fought a number of times varying on the chosen character: If the Player is Lilac, he will be fought 4 times; and if the Player is Carol or Milla, he will be fought 3 times.
Fortune Night Fight
Serpentine is the Mid-Boss of Fortune Night in Lilac's Story. In Adventure Mode, a brief cutscene will play, showing him confronting Lilac and scolding her for "walking into this conflict". After an argument between the two, the cutscene ends and the Mid-Boss Fight begins. After attacking, Serpentine will dash quickly to outflank the Player, alternating directions each time. Once he's taken enough damage, Serpentine will fall back and jump into his ship, which speeds towards Lilac, who runs away to avoid getting hit. Eventually, his ship will eventually hit a brick wall and break in two, with the lower half going through the narrow passage, while the upper half falls on top of Serpentine. In Adventure Mode, when Lilac walks back to the crashed ship, she'll say "You had it coming, Snake Man!". Shortly after the Player enters Zao's Shopping Paradise, Serpentine will break out of his damaged ship to pursue them.
Jade Creek Fight
Serpentine is also the Phase One End-Boss of Jade Creek. After Team Lilac fails to save Torque from being captured by Syntax and taken away via the Absolution, Serpentine appears behind them, itching for revenge. Before this fight, the Player can obtain a Water Shield. Serpentine's attacks are the same as they were in Fortune Night, except one of his attacks have a wider range, making it easier to avoid. Once enough hits are dealt, Serpentine will fall into the background, dropping 3 Life Petals in the process. Then he'll reappear, piloting a Gunship that can deploy Shade Elites to attack the Team.
Serpentine charges up his Plasma Pistol and fires 3 weak shots at the Player. These shots are easy to avoid at point-blank range and can be deflected by Milla's Shield.
Serpentine will take out 2 Plasma Pistols and fires a torrent of shots into the air, which will then land near him. He will also generate a shield to protect himself from attacks while he's firing. This attack's Area-of-Effect is increased during the Boss Fight in Jade Creek, making it easier to avoid. It can also Stunlock the Player if they're careless enough to jump above Serpentine while he's firing. Milla can block the falling shots if she's carrying a Phantom Cube.
Serpentine will launch a stream of flames up and down in the Player's direction while occasionally jumping forward.
If enough distance is put between the Player and Serpentine, he will fire a missile that slowly traces the Player's movement and locks on to them, launching afterwards.
Final Dreadnought 2 Fight
Serpentine is also the End-Boss of Final Dreadnought 2, but this time, he takes the form of a cyber-mutated monster.
At the end of Final Dreadnought 2, the Player will find Serpentine, who appears to be injured. Suddenly, he mutates into a larger, more draconic version of himself, making him faster in a pinch and his attacks dangerously stronger. Before this fight, the Player can get 4 Extra Lives, and a 5th if they time a jump just before the floor gives out. Also, there is a bottomless pit, so the Player must not be reckless with Lilac's Dragon Boost. When close to being defeated, Serpentine's face will break, with one of his eyes hanging out. Once defeated, Serpentine will explode, with only a few parts of his armor left behind, ending the fight and the Stage. During the End Credits, Serpentine is revealed to be alive and turned back to normal, but is in grief over the loss of his robotic arms.
Mutant Serpentine will charge at the Player with a plasma-charged punch, easy to avoid at point-blank range.
Mutant Serpentine can throw the energy from a Plasma Punch onto the ground, causing it to speed towards the Player.
Mutant Serpentine can fire multiple shot simultaneously in 4 different directions, able to inflict Stunlock on the Player. Before firing, laser lights come out of his hand, hinting the direction of each shot. These shots can be deflected by Milla's Shield.
Mutant Serpentine launches a stream of flames that move in a Zig-Zag pattern. The flames can be deflected by Milla's Shield.
- During the Boss Fight with Mutant Serpentine, Carol cannot climb any of the walls right before landing into the Boss arena. This is likely to ensure Carol doesn't escape the Boss Fight.
- Mutant Serpentine shares the same Boss Fight Theme with the Absolution, except it speeds up during the climax of the fight, when he's close to being defeated.
- Strangely, this Theme isn't part of the Game's Official Soundtrack.
- Mutant Serpentine shares a lot in common with Mutant Milla:
- Both are found in Final Dreadnought, with Serpentine in Round 2 and Milla in Round 3.
- Both act as End Stage Bosses.
- Both undergo the same transformation process into Mutant Monsters.
- When Serpentine takes enough damage, he lets out a faint but recognizable scream, similar to how Mutant Milla screams when she takes enough damage.
- After 4 screams, Serpentine's face will cracked, exposing what could be his membrane. This is similar to how Mutant Milla's face is destroyed when she's close to being defeated.