Birthday present to get my friend that likes the Celtics as banter/to make fun of him?

I know nothing about basketball, but I like making fun of my friend that likes basketball. One of my favorite jokes is somehow inserting things about how Lebron is the best player of all time, since he says it’s Michael Jordan.

For his birthday I thought it’d be funny and personal if I got him something that a Celtics fan would hate! Maybe some arch-nemesis, or a season that went really bad, but I really don’t know, anything goes. I want it to be as stupid as possible! Maybe print something on a t-shirt etc.

Any ideas would be welcome :)

BostonVagrant617
27 | a day ago
Mbanicek64
10 | a day ago
gameralex444
12 | a day ago
TheWolfRevenge
2 | a day ago
lanciii | Tommy Point
6 | a day ago
TheWolfRevenge
2 | a day ago
Woof-Good_Doggo
2 | 20 hours ago
Embarrassed_War_6779
2 | a day ago
VerdammtesAutomat | Gamer Hayward
10 | a day ago
slimcullen
1 | a day ago
VerdammtesAutomat | Gamer Hayward
2 | a day ago
champagnesupernova10 | Marcus Smart's Green Hair
5 | a day ago
UTgeoff |
2 | a day ago
Woof-Good_Doggo
1 | 20 hours ago
dbinnunE3
3 | a day ago
lanciii | Tommy Point
1 | a day ago
Boomshakalaka89
3 | a day ago
Minimum_Boat6028
2 | a day ago
slimcullen
1 | a day ago
slimcullen
2 | a day ago
genro_21
1 | 21 hours ago
justbrowsing987654 | White, Jrue, JB, JT, Porzingis, & Big Al
2 | 20 hours ago
Tomatersauce
2 | 18 hours ago
RobMV03 | THE TRUTH
2 | 16 hours ago
ovr_ndr_70
1 | 15 hours ago
the_spinetingler | Parish Punching Laimbeer
1 | 12 hours ago