Best in Odo Losing It---Crossfire

In "Crossfire," Odo gets distracted from finding the one responsible for an assassination attempt on Shakaar by his love for Major Kira. Upset about his poor job performance and his passion for someone he knows he will never have, he flies into a jealous rage and tears up his quarters after seeing Kira and Shakaar together.

Quark gives Odo a little tough love of his own and puts him back on the right path.

Worst of Star Trek: DS9---The Alternate

"The Alternate" is the 12th episode of the second season.

A Bajoran scientist who worked with Odo in a research facility arrives at the space station and informs Odo that he picked up traces of a substance containing DNA similar to Odo's which may hold clues to Odo's origins.

He, Odo, and Dax arrive on the planet in the Gamma Quadrant and find and retrieve an entity and plan to bring it back for study. Their otherwise uneventful trip is interrupted by a violent earthquake that releases gases that render the crew unconscious except for Odo.

As the crew are recovering back on the station, Chief O'Brien puts the alien in a glass containment field.
It continually goes through metamorphosis and grows, eventually breaking out of the container. But later the thing escapes and O'Brien finds what was once the alien hiding in a duct. It had turned to a liquid that looks like the consistency of oatmeal. O'Brien states it is dead.

Later, Dr. Bashir is almost attacked in his lab by a massive blob. This blob resembles Odo in his transitional phase and affects the thermal temperature of its surroundings. The science team collects some residue and sees the DNA patterns matches Odo. The scientist tells Odo this and warns him he may be captured and put on display as some type of freak unless he comes back to the research facility with him. Odo has a psychological and physiological meltdown. Odo becomes the monster again and is contained in a force field. The scientist is able to talk him down.

Later, the gas that affected Odo's physiological structure is removed.

I found this episode confusing. It left many unanswered questions. For one, why did the team remove the pillar from the planet instead of taking images of it and samples to study? The earthquake eruption occurred when the away team transported the pillar to the shuttle. Was the earthquake related to the removal of the pillar?

Second, it doesn't answer who or what the life was that they took back to study. Is it like Odo or a similar life form? That's never made clear. The episode became more about Odo's relationship with the scientist rather than Odo's origins, which are pretty much forgotten by the end.

Another thing I noticed that isn't mentioned much in previous episodes. O'Brien asks Sisko and Kira if security cameras picked up anything during the alien's escape. Funny how security cameras are hardly referred to any other time unauthorized beings enter the station. One example was when an alien entity enters the body of Bashir in "The Passenger" and wonders around the station undetected.

Best of Star Trek: DS9---Necessary Evil

"Necessary Evil" is the eighth episode of the second season and was written by Peter Allan Fields.

SUMMARY

A woman named Vaatrick Pallra offers Quark five bars of Latinum for retrieving something left by her late husband hidden on the station. She won't go to the station herself because she doesn't want to face Odo again. Years before, Odo had suspected her of murdering her husband but found no supporting evidence.

When Quark, with the help of Rom, retrieves the box, a man hired by Pallra to follow Quark, gets the box from him and then shoots him with a phaser, seriously injuring him. Quark and Rom did have a chance to see the contents of the box beforehand---a list of names, all Bajoran.

Now Odo must investigate the attempt on Quark's life while retelling the original investigation, through flashbacks, on how he was hired by Gul Dukat to investigate the murder of  the woman's husband.

Here, we get more background story of the space station during the occupation and Odo's and Kira's first meeting. Turns out Kira knew the victim.  His wife suspected an affair, but Kira has a different story. Odo senses she knows more than what she's telling, but is she telling the truth when Odo checks logs and confirms her alibi at the time was that she was committing an act of sabotage of an ore processor?

But as the investigation unfolds, Odo is conflicted about where the case is taking him and whether or not he wants to go there. "There's no room in justice for loyalty, or friendship, or love. Justice, as the humans like to say, is blind. I used to believe that. I'm not sure I can anymore."

And what about that list? It contained names of collaborators to the Cardassians. Pallra's late husband was part of that group. She was running out of funds and decided to use the names for blackmail to maintain her lifestyle.

Dukat hired Odo because of his neutrality, being neither Bajoran or Cardassian. Dukat wanted to protect the names of his collaborators.

What I liked about his episode is 1) it was fun watching the mystery unfold---like a detective novel in space. 2) we get more character development here, particularly in the back stories of Odo and Kira. We also learn of their great fondness for each other. Kira questions Odo, after her involvement with the murder is revealed, whether or not Odo can ever trust her again. He assures her that they are still friends. But apparently, trust is something she will have to earn again.   

Best of Star Trek: DS9---Dramatis Personae

"Dramatis Personae" is the 18th episode of season 1 and was written by Joe Menosky.

It's trouble from the get-go here when a Klingon vessel en route to the station, after conducting a survey, 

explodes. A Klingon officer is beamed over and he utters "Victory" before dying of severe trauma from weapons fire.

Then there's the matter of a Valerian ship waiting to dock. Major Kira has an issue with the Valerian's whom she claims aided the Cardassians against Bajor and supplied them with weapons. Kira wants their ship 

inspected by Commander Sisko orders her to allow them to dock without interference.

Meanwhile, Odo is questioning Quark to see if he has any information about the true nature of the Klingon 

vessel. As Odo is leaving, he is struck by an invisible shock that manipulates his shape and he passes out. 

In Dr. Bashir's office, Odo awakens and Julian is warning him to choose sides carefully in a power struggle between Kira and Sisko.

On a shuttlecraft to investigate the explosion, O'Brien warns Dax to choose sides and choose carefully. Anyone who is against Sisko is against me, he informs her. 

Dax behavior is peculiar as well. She becomes daydreamy, lackadaisical and forgetful.

Odo downloads the recorder from the Klingon vessel and discovers they encountered an alien composed of 

telepathic energy containing information of a power struggle that destroyed their civilization. Could this be 

what's causing this strange behavior of the crew and their wanton struggle for loyalty and power?

With the help of Dr. Bashir, after charming persuasion, Odo convinces him that saving the space station is within his best interest. Odo unleashes a pulsing burst of energy that releases the entity's control of the crews brains in a cargo bay area where the infected crew had gathered in a showdown.

This sort of reminded me of the TNG episode "Conspiracy," although not quite as creepy. But it was just as suspenseful and this time, unlike in "The Passenger," El Fadil managed playing one influenced by an alien presence to satisfaction. Auberjonois got to be the hero this time, another reason why this episode is a winner! He played it cool, calculating, and diplomatic.