Embryo+

Dark Embryo is a harder version of Embryo that only appears in Red Layer 32 of Infinity Drive, and occasionally Daily Drive.

He has more health than Embryo and his phases are much more brutal. He is also darker in color, hence the name.

Backstory
See Embryo. Dark Embryo is not a separate entity per se, he can be thought of as Embryo on Hard Mode.

Overview
Dark Embryo is similar to Embryo, but the difficulty of all of his phases are heavily scaled up in difficulty. He has twice as much health, his patterns are denser and faster, his rockets are far more numerous with stronger tracking, and he moves more quickly.

The boss consists of 6 separate phases of 1200 HP each. Defeating a phase will cause him to lift off the ground and relocate for the next phase. He can't be damaged while relocating unless hit with a Shutdown, which will cause him to briefly fall to the ground.

Like Embryo, if you stand in his face, he will jump into the air and slam down with a melee attack, like a Buster Titan. This attack is an instant knockdown if it connects. This attack can be Weapon Swapped through on reaction if you stray too close, but try to never trigger it in the first place.

Ideal total score, assuming you do not face Dark embryo on the first layer of the Daily Drive, and including batteries

Phase 1: slow chase
The easiest phase. Embryo will chase you slowly and fire forwards from both of his arms.

Simply stay in his face. As long as you stay far away enough to not be melee'd, and close enough to not be hit by the bullets, you will be fine.

He drops a Powerup after this phase.

Phase 2: easy static radial bullet hell
Embryo will move to the centre of the map and produce a bullet hell pattern.

The spacing is tight, but not too difficult to avoid. Try to maintain medium distance to have enough time to react. Use weapon switches to dodge if you are going to get clipped.

Phase 3: heavy rocket salvos
Embryo will move away from the centre and call in lots of aerial Rockets.

This phase is effortless if you simply slowly circle him, the Rockets can't track you in a circle.

He drops a Powerup after this phase.

Phase 4: fast chase
Faster version of Phase 1. Embryo will chase you quickly and aggressively. He will also backpedal, at which point you should chase him.

It's possible to keep up without Accelerate, though it can help.

Make sure to only make use of static weapons like Propeller Mines or Plasma Shield while he is on the offensive, or they will barely hit him.

This phase is easy for Aubergine since you can freeze him in place with a Singularity if he outpaces you.

Phase 5: difficult static radial bullet hell
More difficult version of Phase 2 and the most difficult phase. The first few patterns can be avoided fairly easily, but he starts to produce extremely fast and tight rings with gaps in them, forcing you to back up to a distance in order to anticipate the gaps and move through them. Therefore, get in your close-ranged damage as soon as you can, then back up to anticipate

Consider saving your powerup from Phase 3 for this phase.

He drops a Powerup after this phase.

Phase 6: dynamic bullet hell + heavy rocket salvos
A fairly difficult phase. In addition to the Rocket salvos from Phase 3, he also produces a rotating circular bullet pattern like regular Embryo's Phase 6, and slowly backpedals.

The best way to deal with this is to stick close to him and move clockwise in sync with the pattern in order to not be hit. The rotation is just quick enough to get out of the way of the rockets.

This phase is very difficult with Aubergine, since hitting him with Singularity stops him in place and defeats the aforementioned strategy. Without Singularity you likely won't deal the necessary DPS to hold chain. You will have to be much quicker on your feet to simultaneously avoid the rockets and his bullet pattern if you want to make any use of Singularity - Accelerate is practically a necessity.

Recommended androids
The main problem is Phase 5 which forces you to keep your distance from him for the later half. This makes Coral and Peanut poor choices.

Starch works fairly well, since her Laser deals at least some damage from far away, and the micro missiles have good range.

Multiplayer strategy
Dark Embryo is significantly more difficult in multiplayer, since he can rapidly shift focus between players. This can cause him to spray practically un-dodgeable projectiles across the map, and make some of his patterns harder to read.

If possible, one player should stick very closely to him to maintain focus, while the other(s) bombard him from a distance and only move in for a Shutdown. The focus player should be the weakest character at long range, ie. Coral, Starch, Lemon etc.

Voice lines
See Embryo. Dark Embryo has the same voice lines, and no dialogue (since he is not encountered in the campaign)

Using Offline Daily Drive to practice the fight
Since you can spoof your computer's date, it's plausible to use Offline Daily Drive to fight Dark Embryo without slogging through 32 layers of Infinity Drive first. All you need is a date which generates a run containing him. One such date is 3 February 2017, where he appears on Layer 7.

Although changing your system clock is the easiest way to spoof your date, it is not recommended as many programs and services rely on your system date being correct to function properly. You can bypass those issues by using a program that spoofs the system clock for a specific program, such as Time Stopper or RunAsDate (x64 version is meant only for 64bit programs so it will not work with the game)

It would be even better if an Offline Daily Drive was found where he appears even earlier. This sheet tracks days which have already been searched for. If you plan to do some searching, avoid the already-marked dates, and mark any dates that you have already tried.

Trivia
He was made as part of a now-abandoned hard mode for the Campaign.