Flowey is one of the first major characters we meet in Horrortale.
In the game, he is only grey, expect for his green eye. However, in the comics, he is usually drawn with yellow petals, and green stem. He has only one big green eye, which covers most of his face. His petals are more pointed. He also doesn't have a mouth. It is unclear how he talks to Aliza.
In the comic, Flowey is the first character Aliza will encounter. He will try to act friendly. Then he will say that neither of them want to stay at ruins. Then Toriel burns him to ash. Aliza will take the ash, and put it in the pot. Then she pours a bottle on him, which she finds in the secret hatch in Toriel's kitchen, and he came back to life.
He says that Toriel will hurt her. Aliza decides to trust and save Flowey, which results in Toriel poisoning her. Then she has hallucinations of Flowey convincing her to kill Toriel. Flowey gives her the bottle. She drinks out of it, gets rid of the poison, and tries to run away with Flowey in her hands. Then she escapes The Ruins and leaves Flowey behind.
She meets him again in the Snowdin forest, after she freezes in fear. He says that he avoids the same thing Sans is escaping from. Then he explains what are the skeletons like.
Aliza-He seems to care about her a lot. He also gives her advice. You could say, that Flowey is Aliza's only friend in the underground.
(note: this is noncanon to horrortale, but has theories on what really happened to Flowey after Frisk's Neutral Run..)
Flowey, like in Undertale. was originally Toriel and Asgore's son Asriel. And also the adoptive silbing of Chara (doesn't appear in the comic) Who had died long before frisk fell down. He was turned into a flower after Alphys injected determination into his dust. Which turned him into a soulless flower. Flowey somehow, when Frisk fell down. Followed them until they both went to Asgore's castle. After Frisk killed Asgore (somehow on accident or on purpose. (unknown) Flowey destoryed Asgore's soul and then absorbed the six human souls and became Photoshop Flowey. He tried to kill frisk until they and the souls defeated him. Frisk could have spared flowey, but the only mystery is that he is now gray (In the game, in the comic he looks like the normal flowey, but still has one eye) and has one eye. It is unknown how he got this appearance. Nothing's known.. (For now)