Lust Object

Kind of the kinky older sister to the Love Interest. A Lust Object is a character who is actively lusted over by another. While a character thinks about holding their Love Interest's hand, and shows a Luminescent Blush in their presence, he will regard a Lust Object with dreams of improbably risque situations, and more often than not, The Nose Bleed.

It's possible for a Love Interest to also be a Lust Object, especially when the protagonist is male and the Lust Object, an attractive female. However, this is usually not the case, as a Lust Object is rarely regarded as anything other than that -- an object to lust over. The gender inversion of this -- a female lusting after an attractive male, is usually Played for Laughs.

Note: A character who simply thinks "sexy" thoughts about their Love Interest is not regarding them as a Lust Object.

For a character to be a Lust Object, they must be thought of as 'objects' to fulfill the sexual or proto-sexual desires of the luster, outside of (or in addition to) any romantic feelings. A good indicator is whether or not the Object speaks during the waking wet-dream. If they don't, or if they only use 'stock' sex-scene phrases, they're probably a Lust Object. If they hold a conversation, or even just speak in coherent sentences, they are probably closer to a Love Interest.

They are often the object of a Stalker with a Crush. A guy who is Mr. Fanservice or a girl who is Ms. Fanservice is almost always this, on both sides of the Fourth Wall.

A Hello, Nurse! is a character who is a Lust Object to everyone, usually Played for Laughs. Eating the Eye Candy is one way for a character to dwell on their Lust Object, while Male Gaze / Female Gaze is a way for the author/artist to emphasize that the Object is being fetishized.

Anime & Manga

 * In Ai Kora, all of the girls are this in Hachibei's eyes. Although the obsession on his part can seem to border on love (and in at least one case it leads to romance, or at least a Love Epiphany), it's really just him lusting over their various "parts"
 * Alviss is this to the Phantom in Marchen Awakens Romance.
 * Misato in Neon Genesis Evangelion to the males in Shinji's class.

Comic Books

 * Sin City has Nancy the stripper. She's the favored "performer" in Kadie's Bar but her main luster is the Heroic Sociopath Marv. It's likely that he is in love with her but isn't fully aware of it.

Film

 * Stifler's Mom from American Pie could count, since while the other boys tend to find relationships, she and Finch only ever seem to have sex once and then that's it.

Literature

 * In Cloud of Sparrows, every section told from Zephaniah's point of view keeps mentioning how much he wants to shag Emily.

Live-Action TV

 * Peter Serafinowicz's character on Black Books was this for Fran. It's made clear that he's a self-important arsehole who Fran can't stand, but it doesn't stop her spending half the episode literally masturbating to the sound of his voice.
 * Tony views Jennifer this way on The Sopranos
 * In Buffy the Vampire Slayer, Spike seems to view Buffy this way. He calls it "love", but she doubts it. Of course, by the end of the series it's definitely love; reasonable minds can disagree about what point that began.

Video Games

 * This happens to Miles Edgeworth at least three times in Ace Attorney Investigations. He has no idea why.
 * EVA serves as this for Naked Snake in Metal Gear Solid 3: Snake Eater. However, he grows to genuinely love her over the course of the story.

Other

 * Pretty much every Sex Bot ever.