Mind manipulation

Influence is the ability to modify the opinion of people, generally by magic. Contrary to the hypnosis, the aimed person keeps his personality, but is inferred in a thought, an idea, a paranoia, an action or a mood in a repetitive and obsessional way. In other cases, it can involve of inferring a mental blocking.

Magic

 * Catherine Madison conjured Bloodstone Vengeance Spell meant to destroy Buffy. Initial symptoms were similar to the ingestion a large amount of alcohol, including euphoria and diminished motor coordination. Over the course of the next few hours, it slowly eradicated the target's immune system.
 * Amy Madison conjured a Love spell around Valentine's Day 1998, on Cordelia, with the beneficiary being Xander Harris, using a locket as talisman. However, the locket actually deflected the spell from enchanting Cordelia, affecting all of the other women in Sunnydale instead. All the women whose spinning Katherine Wexford, Willow, Buffy, Jenny Calendar, Harmony Kendall, Joyce Summers, Drusilla and Amy herself falls obsessionally in love with Xander.
 * Mr. Trick, in the employment of Mayor Richard Wilkins, called upon Ethan Rayne to distract Sunnydale's adult population during a tribute ceremony for Lurconis. Ethan cursed the candy bars that were distributed to adults through Sunnydale High School students. Ethan's curse on the chocolate made adults act as if they were teenagers, leaving much of the city unprotected.
 * Allen Lloyd conjured a spell who place every officer and detective in Kate Lockley's precinct under a curse that would shatter their emotional control, first making them reveal their feelings, but eventually throwing them into total chaos similar to a collective depression.
 * Willow cast a spell to have her will done in an attempt to get over the pain of Oz's departure, but the exact wording she used caused anything she said to come true, though only when she did so inadvertently. With this ability, she rendered Giles completely blind, made Xander a literal demon magnet, and caused Buffy and Spike to become engaged.
 * Willow tried to cast a memory spell with Lethe's Bramble to wipe Buffy and Tara's memories clean of all the negative aspects of what her spells did to them, but she was rushed to do so and carelessly left an entire package of a crucial spell ingredient right next to Buffy's fireplace, which caught fire and gave the entire Scooby Gang, including herself, total amnesia.
 * Brie, a customer, was magically mind-controlled by Amy in the Bronze for a supposed date with Willow.
 * When Ryan and Simon forcibly tried to get Amy back on the dance floor and insulted Willow with homophobic words, Willow and Amy magically trapped the two into go-go cages and skimpy outfits, forcing them to continuously dance.
 * Dark Willow exerting powerful levels of telepathic mind control. This mind control even extended to Anyanka, despite Anya's statement that vengeance demons were immune to mind-controlling magics.
 * Penance Malediction was a form of hex wherein a victim was punished by his or her own subconscious by turning it against himself or herself. Seeking vengeance, and, as later revealed, under orders from Warren Mears, Amy performed Penance Malediction on Willow Rosenberg, who continued to carry feelings of guilt from her murder of Warren. Consequently, Willow transformed into Warren shortly after kissing Kennedy. Over time, the hex caused Willow to be more like Warren not just physically, but also verbally, emotionally and mentally. Willow as Warren began to harm people around her casually and spoke and acted like Warren.

Demon

 * Moloch the Corruptor had the ability to mesmerize and influence the minds of humans, making them believe they loved him and was able to make them perform objectional acts for him such as murder. He apparently could activate this power simply by speaking to them during physical form, and it appeared to carry on in his digital form. According to Giles, this power only seemed to work on impressionable minds and its effects varied between individuals as Fritz became totally devoted to him while Dave, who at first was loyal, betrayed Moloch when he couldn't bring himself to kill Buffy. Willow also broke free from his spell after it became clear that he was evil.
 * The First Evil used the secrets and hantises of the people for drove them to insanity like Angel and Spike to commit acts of violence such as suicide like Chloe, lynching and murder like Andrew Wells and Debbie. According to Caleb's twisted mind, it is seen as a reward.
 * Hans and Gretta Strauss used the emotions of the people, specifically hatred and persecution, to feed, demonstrated on Joyce and Sheila Rosenberg. As such, it would often appear to humans and goad them to bring justice by persecuting witches or females who appeared to have connection to the supernatural.
 * Thesulac Demon use its telepathic abilities to read and whisper to the minds of its chosen victims, taunting them with their hidden fears and insecurities. The fear they inspired not only fed the Thesulac, but also drove the victim to insanity and to commit acts of violence such as suicide, lynching and murder.
 * Rahmon had the ability of causing madness and insanity in those around him. Rahmon's power was unintentionally transferred to a shroud when a high priest bound him in a case, from this point on an image of Rahmon's face could be seen on its surface.
 * The half-demon Billy Blim due to his demonic heritage, had the power to bring out the primal misogyny of any man who touched him like Gavin Park or came into contact with his body fluids (sweat, blood, etc.) like Wesley. Only a man incapable of hate was immune to his touch.
 * Sweet had an ability to cause every being, including other demons, in a given area to burst into singing and dancing, as well as making them feel like they were in a musical, as demonstrated when he lured Dawn into dancing with him.
 * Halfrek posed as a guidance counselor and coaxed Dawn Summers into making a wish. Feeling that no one wanted to spend time with her, Dawn wished that people would never leave; Halfrek therefore cast a spell that prevented anyone from leaving the Summers residence.
 * When Lorne's ability to sleep was removed, his powers were altered; instead of sensing destinies, he began to write them, granting him a sort of suggestion power. He inadvertently altered Spike's cynic personality into optimistic and super-positive, made Wesley and Fred act drunk despite having had very little alcohol, made Gunn literally "stake out his territory" by urinating all over the Wolfram & Hart building, and influenced Angel and Eve to have sex with each other.
 * Courtesan demon were a variety of succubus. Morgan was a member of this inter-dimensional species and has the power to seduce all the men in her reach.

Biologic

 * The She-Mantis release pheromones to attract males, making them smitten by her very presense. It don't work on Vampire.
 * females lived bound to servitude to the males in their home world. In order to make women submissive and easily controlled, their ko were removed in a painful process.

Ghost

 * Maude Pearson harassing and growing all women living in her appartment like Cordelia Chase to the suicide.

Objects

 * Spin to Win was a mystical 'Wheel of Fortune' game invented by magician Lee DeMarco, owner of the Tropicana casino. The unlucky victims of this scam became virtually lifeless "zombies" capable of doing nothing more than endlessly playing rigged slot machines.
 * The Brooks letterman jacket was a Sunnydale High School varsity jacket worn by the males of the Brooks family, being passed down to R.J. Brooks around the time of the school's reopening in 2002. It carried a love spell that made Dawn Summers, Buffy Summers, Willow Rosenberg, and Anya Jenkins fall obsessionally in love with him.
 * Humans with prolonged exposure from the corrupting energy of the Seal of Danzalthar would eventually lose their own will, ad would slowly be transformed into servants of the First, in the same manner as the Harbringers.

Mecanic

 * Adam control Riley Finn via his Behavior Modifier, a chip was tied directly into his central nervous system through the thoracic nerve.