Basil (enemy)
Basil is a boss in OMORI. He attacks you at the night of one day left.
Story
"After all this time... you've finally come back for me. But... tomorrow... you're going away. H-HOW COULD YOU DO THAT!?!?" -Basil, before his boss fight
When you wake up during one day left, you can choose to go back to sleep, or you can go upsatirs to Basil's room to save him. Basil is standing there, armed with garden shears. He starts crying, and begs Sunny not to leave him. When Sunny tries to, his Something is at the door, and prevents him from leaving. Basil's Something manifests as well, and they push the two boys into a fight.
Battle
Basil's boss fight is scripted. Neither side can inflict enough damage to kill the other. Sunny starts the fight with the Afraid emotion, and anytime he tires to use a skill, such as Calm Down, it fails and disappears from the Skill selection menu until there are none left. At that point, you have to attack, dealing minor damage. Once Sunny's energy meter reaches 10, he obtains the Stressed Out emotion, which is never used anywhere but this fight. Once Sunny reduces Basil to low HP, Basil uses an attack that brings Sunny down to 1 HP, and permanently damages his right eye, ending the fight.