You got an invitation to Birthday Battler's party, for well... his birthday; even if you've only seen him once or twice.
You decide to go to the place mostly due to respect, and it really wasn't a bad decision... this place looks spectacular. The seats and tables are white with red embroidery, plus there are a bunch of balloons of either red, blue, green, yellow and pink on each table tied to large white sticks that are on top of the tables; the balloons are presumably glued together with some tape.
There are a lot of red party hats for guests to use in all the tables, and some signs that no one knows why are there: one advertising Bloxy Cola, another having a meme of a guest, and the last one advertising some sort of bad quality game called Cookie Clicker.
There's also gifts from other people on a table at the right; also, there's another table on the right that has some superballs and trowels; and finally, there is a DJ booth and dance floor area, which, although not the main focus, really looks interesting and functional.
After entering for a few seconds, Birthday Battler notices your humble presence at his party, so he welcomes you in the best possible way he can give you.
Birthday Battler: "Hello! Welcome to my party! Take a seat whenever you want and where you like! And enjoy this little celebration I made."
Obviously you and he wouldn't be alone at this celebration; there are also a lot of other Robloxians in the place, enjoying anything that's in the place.