Avengers Mansion

After all the light show ended Venom found itself on a vent duct, venom decided that the best course of action was to identify where it was and find a host before get without nutrients and die, crawling through the ventilation the symbiote heard a strange noise coming from a vent that led to a room.

Inside the room there was a woman and a man, the woman was a red-haired and the man had black hair, after a few seconds using the previous host's memories Venom recognized them as Natasha Romanova(Black Widow) and Tony Stark(Iron Man).

They were alone on a meeting room discussing something, Venom couldn't just jump there and attack them, it needed to be patient so it started to pay attention on what they were talking about.

"That Black-out on the helicarrier wasn't normal, it happened on the same moment that we were sending that alien goo to another dimension, the Symbiote must have infected someone or have an ally on the helicarrier" Black Widow said to Tony.

"Nah, it's probably just a mechanical mistake on their generator, its an old machine, fails happen but in one way or another the goo was sent to another dimension" Tony answered Natasha unworried.

"I have the feeling that this isn't a good sign, i can feel the bad luck smell in the air" Natasha said while looking around, when she was looking at the vents she felt that someone was watching her.

"We should make a new test tomorrow, if the alien is here or not" Natasha told Tony.

"I'm not gonna continue with a conversation that its not going to take us anywhere so good night, have fun with your teories" Tony said as he left the room

Natasha was a bit annoyed, Tony didn't care about this but Natasha knew that this was going to end bad

As the meeting was over, Natasha decided to stay on that room to analyze the video of the helicarrier and make some analysis of strange energy around the city.

When Natasha was analyzing a map, a vent was open and a black tentacle was getting closer to Natasha, but the red-haired felt danger coming and grabbed the tentacle before it could reach her, but that was her mistake, the tentacle melted on her hands and tied them, the tentacle pulled her and held her in mid-air with her arms up.

Suddenly a large amount of goo fell on the table and the symbiote formed the classic venom suit but this time there were breasts.

"So, i heard a lot about you black widow, the red-haired agent who kills anyone who stands on her way, i have to say, you're the perfect tool to reach our goals" Venom said as he put a foot on the chair of the table and looked directly to Natasha

"And what would this goal be?" Natasha asked with her disgusted expression, she didn't look worried but she knew that a bad situation was going to get worse

"What more could be ? We will share our bond to every single living being, starting on earth and then expanding our empire to other worlds, galaxies and even the cosmic beings." Venom answered as he grabbed the chin of Natasha.

"If you're looking for an ally you're not going to have it with me, i have loyalty with my world and if i have to destroy you to protect it, then so be it" Natasha answered coldly

"You know, We really hate those who try to ruin our plans, but once you're bonded with us you're gonna become our ****, you're gonna agree with everything we say, you're gonna love it and never want it to end" The symbiote said as it turned it back to Natasha and opened itself as an empty bodysuit full of tentacles inside.

"Come inside darling, you're gonna have a wonderful time" the symbiote said as it untied her hands and grabbed her limbs with several tentacles pulling her to the symbiotic suit.

"NO DON'T!" Natasha yelled trying to pull out, but her resistance was futile as she was pulled into the bodysuit and the tentacles wrapped her up, covering her mouth with a tentacle and absorbed her spy suit.

The symbiotic suit slowly took the appearance of her spy suit but she could feel even more tentacles inside the suit, rubbing her clitoris and nipples and the tentacles penetrating her mouth and asshole, suddenly she could hear a voice that wasn't the symbiote, but was her mind

"Do you really wanna escape? The symbiote told you, this is heaven, you'll never have more pleasure in your life"

"Shut up, this isn't real, there is no such paradise"

"Oh, but there is, you'll never forget this pleasure, and even if you're able to escape, the symbiote already left his seed, so your life is doomed"

"NO! YOU'RE LYING"

"Why should I? Just enjoy this moment and forget about this world"

"SHUT THE FUCK UP" she shouted inside her mind as she started to pull the fake spy suit of her body, the suit fought back trying to keep her inside, but Natasha kept pulling it until her mouth and breasts were exposed.

Natasha was exhausted after that, but she kept pulling the suit of, she could see that the inner part of the suit was made of black tentacles, she kept pulling it out of her body until only her hands and feet were covered, she was too tired to continue, the floor had several pieces of her symbiotic uniform but the goo wasn't moving anymore, then she fell on her knees due her exhaustion.

She was on the table hoping that someone would open that door and help her, that room was one of the safest rooms on the mansion, but it was sound prof and had no cameras or access to Jarvis, so she could only wait there until she get some energy back or someone found her, hoping that the goo doesn't move anymore.

Then she started to feel pain, like her insides were being torn, Natasha fell off the table and the pain increased, she wanted to scream but she couldn't, the pain was getting bigger, Natasha didn't know what was happening but she could feel a weird movement on her crotch.

The pain stopped but the movement on her crotch continued, then suddenly a large tentacle popped out of her vagina and plugged in her ass.

Natasha couldn't believe what was happening, she was horrified of what was going on with her, she didn't want to see the tentacle again, but then another tentacle came out of her, and another one, and another one, after a few seconds more than ten tentacles were popping out of her holes.

The tentacles moved like they were alive, and in fact they were, they were growing a body, the upper body of a woman formed, the face and the arms, after the upper body formed, a pair of breasts started to grow, they were big, they were huge, her breasts were now double D size.

Her body was beautiful, the hips and the ass were the most curvy and perfect that Natasha had ever seen, the thighs were also amazing, the skin was a pure black and the face of it was a latex-made version of Natasha's face, the symbiotic women hugged Natasha and started kissing her.

"You should have stayed with us, you would have so much fun, but don't worry, our seed is going to make you change your mind" the symbiote said as the black figure kept rubbing her breasts on the head of the red-haired agent.

Suddenly Natasha's nipples started to grow and lactate a black liquid, she didn't know why was happening but she was scared, she didn't want the liquid touching her body but it was impossible to avoid, the goo kept flowing, until her entire body was covered, she was once again wearing a Symbiotic suit but this time she was exhausted and unable to resist.

The symbiote didn't waste any second and entered Natasha's vagina and ass, her body was absorbing the black liquid, it was an incredible amount, she could feel that the symbiote was making changes on her body, and her body was accepting them, suddenly she could feel a strange heat coming from her crotch, the heat was increasing, but she didn't care, the heat was making her horny, and the hornier she was the more heat she could feel, the symbiote was creating an infinite loop of pleasure and lust, the heat was so much that she couldn't control her body, and her pussy started to secrete the same liquid that her breasts were lactating, her body was now fully under the control of the symbiote.

She was laying on the ground with her ass and legs in the air, the liquid was covering her body like a cocoon, her nipples were lactating the symbiotic seed, the heat was getting unbearable, she was almost reaching her climax.

"CUM FOR US"

She came with a huge orgasm, the liquid covered her face and she fell on her back, the orgasm lasted for a whole minute and Natasha could feel the symbiote on her skin.

"Now you're truly ours, do you still think that the symbiosis is bad?" The symbiote said as she rubbed her hand on her breasts.

"Yes, its not bad, its amazing" Natasha answered moaning as she played with her pussy.

"Do you like your new form?" The symbiote asked

"Yes, it's amazing" Natasha moaned.

"Good, and now we'll share the gift with the others, and you'll lead the way"

"Of course, let's start the symbiosis"

The cocoon was gone, and Natasha's body was completely transformed, she was wearing a fully black tight latex suit except by her face, she opened her arms and the black puddle of Symbiote jumped toward her breasts, it got absorbed on her breasts as a white spider symbol appeared and her body started to change, her breasts got bigger and her ass got thicker, her thighs and lips also grew a bit and her eyes and hair became black, after the change was finished she opened her eyes, she had a cold and lustful look on her face.

"We are the venom, we are the darkness, we are the pleasure, and we are the future" Natasha said with a deep voice as she looked around, then a big smile appeared on her face, she put her hands on her hips and started laughing, then she went towards the door as the Symbiote changed itself to her spy suit and her appearance came back to normal.