<s>
In	O
video	O
games	O
,	O
a	O
raid	B-Protocol
is	O
a	O
type	O
of	O
mission	O
in	O
massively	B-Protocol
multiplayer	I-Protocol
online	I-Protocol
role-playing	I-Protocol
games	I-Protocol
(	O
MMORPGs	B-Protocol
)	O
where	O
a	O
number	O
of	O
people	O
attempt	O
to	O
defeat	O
either	O
:	O
(	O
a	O
)	O
another	O
number	O
of	O
people	O
at	O
player-vs-player	O
(	O
PVP	O
)	O
,	O
(	O
b	O
)	O
a	O
series	O
of	O
computer-controlled	O
enemies	O
(	O
non-player	O
characters	O
;	O
NPCs	O
)	O
in	O
a	O
player-vs-environment	O
(	O
PVE	O
)	O
battlefield	O
,	O
or	O
(	O
c	O
)	O
a	O
very	O
powerful	O
boss	O
(	O
superboss	O
)	O
.	O
</s>
<s>
In	O
military	O
real-time	O
strategy	O
(	O
RTS	O
)	O
games	O
like	O
StarCraft	B-Application
,	O
"	O
raids	B-Protocol
"	O
usually	O
refer	O
to	O
the	O
military	O
tactic	O
.	O
</s>
<s>
Raiding	B-Protocol
originated	O
in	O
the	O
class	O
of	O
text	O
MUDs	B-Application
known	O
as	O
DikuMUD	B-Application
,	O
which	O
in	O
turn	O
heavily	O
influenced	O
the	O
1999	O
MMORPG	B-Protocol
EverQuest	B-Protocol
,	O
which	O
brought	O
the	O
raiding	B-Protocol
concept	O
into	O
modern	O
3D	O
MMORPGs	B-Protocol
.	O
</s>
<s>
As	O
of	O
2019	O
,	O
the	O
largest	O
and	O
most	O
popular	O
game	O
to	O
feature	O
raiding	B-Protocol
is	O
Blizzard	O
's	O
2004	O
MMORPG	B-Protocol
World	B-Protocol
of	I-Protocol
Warcraft	I-Protocol
.	O
</s>
<s>
The	O
combat	O
encounters	O
comprising	O
a	O
raid	B-Protocol
usually	O
require	O
players	O
to	O
coordinate	O
with	O
one	O
another	O
while	O
performing	O
specific	O
roles	O
as	O
members	O
of	O
a	O
team	O
.	O
</s>
<s>
The	O
roles	O
of	O
Tank	O
,	O
Healer	O
,	O
and	O
Damage	O
Dealer	O
are	O
known	O
as	O
the	O
"	O
Holy	O
Trinity	O
"	O
of	O
MMORPG	B-Protocol
group	O
composition	O
.	O
</s>
<s>
A	O
raid	B-Protocol
leader	O
is	O
often	O
needed	O
to	O
direct	O
the	O
group	O
efficiently	O
,	O
due	O
to	O
the	O
complexities	O
of	O
keeping	O
many	O
players	O
working	O
well	O
together	O
.	O
</s>
<s>
Raids	B-Protocol
are	O
often	O
very	O
rewarding	O
in	O
terms	O
of	O
virtual	O
treasure	O
and	O
items	O
that	O
are	O
unique	O
or	O
that	O
grant	O
exceptional	O
stats	O
and	O
abilities	O
,	O
thus	O
giving	O
players	O
an	O
incentive	O
to	O
participate	O
.	O
</s>
<s>
Players	O
have	O
invented	O
various	O
systems	O
,	O
such	O
as	O
Dragon	B-Protocol
kill	I-Protocol
points	I-Protocol
to	O
distribute	O
loot	O
fairly	O
.	O
</s>
<s>
Raiding	B-Protocol
is	O
often	O
done	O
by	O
associations	O
of	O
players	O
called	O
guilds	O
or	O
clans	O
who	O
maintain	O
a	O
consistent	O
schedule	O
and	O
roster	O
.	O
</s>
<s>
There	O
are	O
two	O
types	O
of	O
raiding	B-Protocol
guilds	O
:	O
casual	O
guilds	O
,	O
defined	O
as	O
spending	O
two	O
to	O
three	O
days	O
per	O
week	O
on	O
average	O
;	O
and	O
hardcore	O
guilds	O
,	O
defined	O
as	O
spending	O
four	O
to	O
seven	O
days	O
per	O
week	O
on	O
average	O
.	O
</s>
<s>
The	O
fact	O
that	O
raids	B-Protocol
often	O
require	O
multiple	O
consecutive	O
hours	O
of	O
constant	O
gameplay	O
leads	O
some	O
to	O
believe	O
it	O
is	O
a	O
physically	O
unhealthy	O
activity	O
.	O
</s>
<s>
A	O
2003	O
study	O
by	O
the	O
National	O
Institutes	O
of	O
Health	O
found	O
that	O
playing	O
MMORPGs	B-Protocol
for	O
more	O
than	O
20	O
hours	O
per	O
week	O
correlates	O
with	O
obesity	O
and	O
nutritional	O
imbalance	O
as	O
well	O
as	O
an	O
increased	O
propensity	O
for	O
bone	O
loss	O
and	O
muscle	O
atrophy	O
.	O
</s>
<s>
Due	O
to	O
these	O
concerns	O
,	O
China	O
has	O
proposed	O
national	O
limits	O
on	O
how	O
long	O
people	O
can	O
play	O
MMORPGs	B-Protocol
.	O
</s>
<s>
The	O
measures	O
will	O
impose	O
penalties	O
on	O
people	O
who	O
play	O
MMORPGs	B-Protocol
for	O
more	O
than	O
3	O
hours	O
per	O
day	O
.	O
</s>
<s>
Game	O
raids	B-Protocol
are	O
commonly	O
organized	O
by	O
internet	O
celebrities	O
with	O
the	O
intent	O
to	O
protest	O
against	O
the	O
company	O
's	O
behavior	O
,	O
their	O
actions	O
or	O
simply	O
for	O
fun	O
.	O
</s>
<s>
A	O
popular	O
raider	O
is	O
Quackity	O
,	O
who	O
streams	O
his	O
raids	B-Protocol
on	O
Twitch	O
.	O
</s>
