A/N: I suggest you don't read this if you are scared of spiders. Although, I wrote it and I'm terrified of spiders.
It all began with a spider. Just a tiny insignificant arachnid caused the almost complete loss of sanity in the Scouting Regiment 104th squad recruits. Some blame Eren (mainly Jean). Some blame Armin. Mostly everyone blames Hanji. Not to mention Levi and Erwin were also dragged in.
Hanji was bored. That was never a good thing. When Hanji was bored she would conduct an experiment. Mainly she only experimented on Eren, but she can only come up with so many experiments for him.
As it was, she was in the mess hall when it happened. It was nearing the end of dinner, so most people were either just finishing up their food or talking to friends before they went off to their quarters to prepare to bed. Her eyes lingered on the Titan Shifter at the next table over, as they always did, when he suddenly stopped talking and stared at a place on the table. His head leaned forward ever so slightly when suddenly he leapt back and shrieked, causing everyone's heads to swivel over to look at him. He stood ten feet away from the table, pressed against the wall with his eyes wide as saucers. Hanji raised her eyebrows and looked back to the table he was previously sitting at to see Mikasa grumbling and reaching across the table with a cloth.
"Eren," She called in slight annoyance. "It's dead. You can come back now."
"Are you sure?" He asked quietly, his voice shaking. The entire hall was still staring on with interest. Mikasa nodded and flicked at the table. Eren slowly made his way back to the table and sat down.
"A spider? You screamed like a little girl over a spider?!" Jean asked. After receiving an embarrassed glare from Eren, he burst into hysterical laughter.
"Shut up, horseface!" Eren yelled, burning holes in Jean's head with his eyes. Jean just continued to laugh as he banged his fist on a table.
"Eren's been irrationally afraid of spiders since we were kids." Armin mused, a small smile on his face. Hanji liked Armin. He was the smartest of the new recruits (if not most of the Scouting Regiment) and he assisted her with her experiments.
A grin curled her lips as she continued to watch Eren defend himself. Oh, this was going to be so much fun.
Hanji made a plan for her experiment. She wanted this to be as fun as possible, so just asking the people their irrational fears would be stupid. First on her list was Armin. Armin would probably be easy to figure out and he could help her once she knew. But, before she started with Armin, she wanted to do something with Eren.
About ten minutes before the wake up call the day after the spider incident, Hanji crept her way down the halls to the basement. She had a small glass jar in her hand with a large hairy spider inside. She had made sure that it was not poisonous just in case. Hanji giggled to herself as she slid down the railing to the basement. The guard on duty jolted awake and saluted. He opened his mouth to greet her, but she slapped her hand over his mouth.
"Be quiet and leave, I have an experiment to do." Hanji hissed. The guard nodded hurriedly and swept out of the room as quickly as possible. Hanji grinned widely as she entered the cell. Eren was sleeping peacefully, drool running down his cheek and his hair a mess. She stifled a laugh as she popped the lid off the jar and pushed the arachnid onto Eren's pillow. It scurried forward a few inches before stopping right in front of his closed eye. After Hanji assured herself the spider wouldn't move any further unless provoked, she slipped out of the cell to hide in a shadowy corner with her clipboard.
Eren knew when he had to wake up even in dead sleep by now. After three years of the same time, he would be up at the precise second. His eyes slowly slid open as he yawned groggily. Then, he saw it. A big, hairy, disgusting spider not two inches from his face. His yawn turned into a shriek as he sprung out of bed and bolted to the door (which was unlocked because Hanji forgot to relock it). In only his boxers and a shirt, he sprinted up the stairs.
"Mikasa!" He screamed as he ran to her room as fast as his legs could carry him. He threw open the door to the room she shared with Christa and jumped onto Mikasa's bed. She jolted upright in surprise and was dumbstruck upon seeing Eren's tear-streaked face.
"Wh-What is it, Eren?" She asked groggily still only half awake. His eyes were wide and terrified like he had just seen a ghost.
"Th-There was a huge sp-sp-spider on m-my pillow!" He sobbed, his voice cracking as he clung to Mikasa like she was a lifeline.
"A-Ah!" Christa squeaked from across the room. "Eren? What are you doing here!?"
"Spider." Mikasa answered for him as she rubbed her brother's back soothingly. At this point, Eren was shaking and sobbing uncontrollably and on the verge of a full blown panic attack. This was the point where Hanji decided to burst in.
"Eren! I'm sorry! It was for science!" Hanji exclaimed loudly as the door slammed against the wall. Eren barely even heard her. "Eren!? Are you okay?! D-"
"Hanji!" A voice barked from behind her. It was Levi. "What the hell is going on!? Why was the brat running through the halls screaming at the top of his damn lungs?!"
"Eheheh, you see Levi, I was conducting an experiment and-" Levi held up a hand to silence her.
"Did you put a spider on him or near him?" He asked, sighing in annoyance. Hanji just grinned apologetically and shrugged. "Eren, you get the day off. Hanji, next time, you're cleaning the stables by yourself. Got it, shitty glasses?"
"Yes, Levi." Hanji pouted before sulking away. Eren was still clinging to Mikasa as sobs wracked his body. Humanity's Hope was scared of a spider.