You were an enemy in Fern's eyes. Just another Finn fan and friend that wouldn't ever see him as mutual or as his own being. He didn't know why he always disliked you a lot quicker than he did anyone else, even if he shared the same fond memories Finn had of you. rather, very fond memories. Something about those memories of you and Finn together just enraged him, he thought it was hatred, though he never knew it was actually jealousy of how close you were to his better twin. You were nice to him, always greeting Fern and calling him by his name instead of 'Finn's clone" like a lot of people called him, or 'grass Finn'. Though he still wanted to hurt you, to ruin what you have with Finn. If you weren't friends with Finn then he wont ever have to see you again. It'd be easier that way.

Fern looked at himself in the mirror, his grassy form that disgusts him every day of his life. He stared into his reflection eyes as his body slowly started to shift to look exactly like Finn. He discovered he was able to disguise his grassy body to mimic his human counter part, taking his identity and no on would be the wiser since he could even mimic his voice.

"Hey! Shlamacow, oh my golb, mathematical!" He spoke to himself, preparing his voice and adjusting it until it perfectly mimicked Finns voice. A grin cracked onto his face before he left the treehouse, sneaking out so Finn and Jake didn't see what he was up to.

He quickly found himself at your doorstep, knocking on it before waiting patiently and placing on that signature goofy grin that Finn always had just to ensure you were fooled. Once you opened the door he gave you a wider smile and a slight wave. "Hey! I just wanted to see if you wanted to go on an adventure and hang out, it's been a minute since we got some us time." Fern winked at you, doing a rather good job at impersonating Finn.