Lukadrinette

Lukadrinette is the polyship ship between Adrien Agreste, Marinette Dupain-Cheng and Luka Couffaine from the Miraculous Ladybug fandom.

Canon
Marinette and Adrien both met Luka on his boat house during the music festival, and while Adrien is Marinette's long held crush, just as Ladybug is Adrien's, Marinette had began to develop feelings for Luka shortly after she met him; who also has a crush on Marinette. Because of this Marinette begins to question her old and new feelings for the two boys, which is why she froze in front of them when they both offered a hand that would allow her to get back up from the spot she ended up in after she fell and slid on the ice, as she felt on her end that she has been placed in a position where she might have to decide between the two.

Season 2
Captain Hardrock
 * The end card is of Marinette blushing, while she is "standing" between Adrien and Luka, who might be looking at each other with a smile.

Frightningale
 * The trio are seen dancing together in a scene of Clara Nightingale's music video, with the two boys wearing a Ladybug mask while Marinette's is of a black Chat Noir mask.

Frozer
 * When Marinette tripped and fell at the ice rink, both Adrien and Luka officered to help her back up while smiling at her.

Fanon
The ship could simply be due to Marinette having romantic feelings for both boys, who are friends of hers and have their own romantic feelings for her.

Some have Adrien view Luka as a love rival for Marinette's affections, once he begins to develop feelings for her alone, consciously or unconsciously.

Fandom
FAN FICTION

TUMBLR

Trivia

 * According to Feri González, Luka isn't limited to the role of alternate love interest, the same with Kagami Tsurugi.
 * All three of them are Jagged Stone fans.
 * Adrien had once played the part of keyboard player as a guest member in Luka's band, Kitty Section, while Marinette had designed costumes for the rock band.
 * Even though Adrien wasn't playing with them during that time.
 * Luka's younger sister, Juleka is one of Marinette and Adrien's classmates.

Variations

 * Adrienette refers to the ship between Adrien and Marinette
 * Lukadrien refers to the ship between Luka and Adrien
 * Lukanette refers to the ship between Luka and Marinette