In the popular video game Minecraft, food (such as cake) can heal your character.
Going "cakeless" is the act of ignoring the cake, and any potential health that it can give you, so you can be a badass instead.
The act of going "cakeless" was developed and popularized by Ray (Brownman) from Achievement Hunter, a popular YouTube Channel.
Person 1: Hey! Why didn't you eat that cake, you would have gained extra health!!
Person 2: Nah, I'm going cakeless
Jillen is slang for someone that's lame and cool at the same time.
Person A: Yo, what are you doing tonight?
Person B: Not much, I'm just chillin like Jillen
A mantacorn is a strange hybrid between a Manta Ray and a Unicorn. This animal only exists in strange LSD-induced dreams, and in the minds of young children!
Person A: Woah, trippy
Person B: What do you see?
Person A: A mantacorn!
Person B: You're an idiot
It's when you watch a movie online in your pajamas while chatting with people, instead of going somewhere in real life.
Person A: Hey man, wanna hang out later?
Person B: Nah, I'm going to a Pajamarama tonight.
Person A: You suck!
Person B: But we're watching Space Jam!
Slaymode is a term used to describe the state of mind that occurs whenever a professional gamer starts to play very seriously and annihilates all his opponents.