Sonic and Sash: Tides of Chaos (named Sonic and Lilac: Tides of Chaos in volume 1) is a crossover between the Freedom Planet and the Sonic the Hedgehog universe, written by SonicChaosEmerald. The fan fiction currently consists of 293,988 words and 54 chapters total spread around three volumes.
In volume 1, Dr. Eggman has become desperate as he is running low on energy, not enough to build his Space Station, the Death Egg Mk III. When Orbot, one of his two right hands, suggests to look for another viable energy source, their scanner quickly picks up the energy emitting from planet Avalice; a source of energy stated to have nearly as much as the Master Emerald itself. Unable to move the Death Egg in its current state, Eggman decides to take the planet Avalice out of its orbit and warp it through the use of a dimensional hole to the vicinty of Mobius.
In the process, the seven Chaos Emeralds get shattered accross the now neighboring planet. With the Emeralds falling from the sky, it doesn't take too long for Lilac and her friends to notice their sudden appearance, which starts the search for them all over again.
This fanfic provides examples of the following tropes:
- Age Lift: All characters in the Sonic the Hedgehog universe, whose ages usually stay the same, are stated to be a bit older than their canon counterpart. For example, Sonic, canonically aged 15, has turned 16.
- Alternate Timeline: In-universe, the events of Tides of Chaos take place two weeks after Sonic Lost World and roughly one year after Freedom Planet. The story diviates from the respective canon timelines at that point. Although, its story arcs still feature villains and events seen in games that take place after.
- Bathtub Bonding: When Sonic and Lilac sit together in the healing spa in chapter 1, she talks with him about what happened a year ago, recapping the events of Freedom Planet. Lilac admits to be getting very emotional whenever the invasion by Brevon is mentioned. Sonic assures her, stating that she should always stay strong and that it's best to look forward. He also adds that life is no fun if the outlook on it is bad.
- Bloodier and Gorier: Both source materials don't usually feature blood. This fan fiction describes the injuries inflicted towards characters and doesn't hide the fact that they bleed."...her appearance had her outfit torn in several places and a bit bloody from her damage she had been hit by from the robot, but she was still conscious, ..."
- Captain Obvious: Justified. Orbot has to explain the obvious meaning behind Dr. Eggman's words, as Cubot is too oblivious.Eggman: "Perfect! The planet extraction is a success! Soon I'll be eating that limitless energy out of the palm of my hand!"
Cubot: "Ehr, boss? I don' think ya c'n eat energy. Ya can use it ta fuel the worker bots though! That'll make it useful!"
Orbot: "Cubot, I'm pretty sure that's what he meant. He was using an expression to demonstrate as to how easy it was to get the energy from the other planet by dragging it out of its planetary orbit and into our solar system."
Eggman: "Yes, thank you, Orbot."
- Continuity Nod: There is quite a lot of them.
- Mystic Ruins and Station Square were two prominent locations in Sonic Adventure.
- Eggman states to have already used his planetary grappler in the past to get a grip of Little Planet and the "Wisp Worlds". This a nod to the events of both Sonic CD and Sonic Colors.
- The Heavy Egg Hammer, an enemy from Sonic Heroes (in the story referred to as Mallet Titan), makes a return, and a big one at that. Lilac and Neera, two exceptionally skilled fighters who have dealt with robots before, weren't able to put a dent on it and were nearly beaten up as they weren't aware of its weakspot, the area under its helmet.
- In chapter 3, Tails mentions the military task force G.U.N and the Space Colony Arc, which were featured prominently in Sonic Adventure 2.
- Conveniently Close Planet: Justified, as Eggman, by force, moved Avalice to the near vicinity of Mobius.
- Actually, to the point that, in chapter 3, according to Tails, their atmospheres overlap. Carol even questions why they aren't affected by gravity, to which Tails responds by stating that the planets still stand far enough away from each other.
- Comically Small Bribe: Carol offered a jewelry store owner a few crystals shards in exchange for a Chaos Emerald, and she actually succeeds.
- Harmless Freezing: In chapter 1, Sonic was still perfectly fine after Neera-Li froze and, later on, freed him.
- Name and Name: Sonic and Sash.
- Moment Killer: Sonic and Sash were having a moment of silence, but were interruped by Carol's emergency call.
- Racing the Train: Near the end of the Chase Scene in chapter 1, Tails notices the oncoming train tracks and comes up with an idea. While he flies through the crossing gates with his plane, Carol uses the construction rumble as a ramp. The two make it Just in Time, but the same can't be said for their pursuers, who collide with the train and cause it to explode. To make this moment even more badass, Carol and Tails didn't even look back afterwards.
- Suggestive Collision: In chapter 3, Sash and Sonic have a race through Green Hill Zone. Sonic accidentally trips over and crashes into her, ending up with the two in a (for them) embarrassing position.