<s>
CryptoKitties	B-Protocol
is	O
a	O
blockchain	B-Protocol
game	I-Protocol
developed	O
by	O
Canadian	O
studio	O
Dapper	O
Labs	O
.	O
</s>
<s>
The	O
game	O
allows	O
players	O
to	O
buy	O
,	O
sell	O
,	O
and	O
create	O
NFTs	O
using	O
on	O
Ethereum	B-Application
.	O
</s>
<s>
The	O
game	O
's	O
popularity	O
in	O
December	O
2017	O
congested	O
the	O
Ethereum	B-Application
network	O
,	O
causing	O
it	O
to	O
reach	O
an	O
all-time	O
high	O
in	O
the	O
number	O
of	O
transactions	O
and	O
slowing	O
it	O
down	O
significantly	O
.	O
</s>
<s>
CryptoKitties	B-Protocol
is	O
the	O
first	O
major	O
game	O
to	O
use	O
blockchains	O
,	O
and	O
one	O
of	O
the	O
earliest	O
examples	O
of	O
a	O
blockchain	O
project	O
designed	O
for	O
recreation	O
.	O
</s>
<s>
Players	O
must	O
purchase	O
Ether	B-Application
cryptocurrency	O
to	O
join	O
the	O
game	O
,	O
and	O
spend	O
it	O
to	O
perform	O
each	O
breeding	O
and	O
trade	O
action	O
within	O
the	O
game	O
.	O
</s>
<s>
A	O
CryptoKitty	B-Protocol
does	O
not	O
have	O
a	O
permanently	O
assigned	O
gender	O
.	O
</s>
<s>
CryptoKitties	B-Protocol
operates	O
on	O
Ethereum	B-Application
's	O
underlying	O
blockchain	O
network	O
.	O
</s>
<s>
Each	O
CryptoKitty	B-Protocol
is	O
a	O
non-fungible	O
token	O
(	O
NFT	O
)	O
.	O
</s>
<s>
CryptoKitties	B-Protocol
cannot	O
be	O
replicated	O
and	O
cannot	O
be	O
transferred	O
without	O
the	O
user	O
's	O
permission	O
even	O
by	O
the	O
game	O
developers	O
.	O
</s>
<s>
Users	O
can	O
interact	O
with	O
their	O
CryptoKitties	B-Protocol
,	O
having	O
the	O
ability	O
to	O
buy	O
,	O
sell	O
,	O
and	O
sire	O
(	O
breed	O
)	O
them	O
.	O
</s>
<s>
However	O
,	O
the	O
CryptoKitty	B-Protocol
art	O
is	O
not	O
on	O
the	O
blockchain	O
and	O
is	O
instead	O
owned	O
by	O
Axiom	O
Zen	O
.	O
</s>
<s>
The	O
company	O
released	O
some	O
of	O
the	O
art	O
under	O
a	O
new	O
'	O
Nifty	O
 '	O
license	O
that	O
lets	O
players	O
use	O
the	O
image	O
of	O
their	O
CryptoKitty	B-Protocol
in	O
a	O
limited	O
way	O
.	O
</s>
<s>
A	O
test	O
version	O
of	O
CryptoKitties	B-Protocol
was	O
unveiled	O
at	O
ETH	O
Waterloo	O
on	O
October	O
19	O
,	O
2017	O
,	O
an	O
Ethereum	B-Application
hackathon	O
.	O
</s>
<s>
On	O
March	O
20	O
,	O
2018	O
,	O
it	O
was	O
announced	O
that	O
CryptoKitties	B-Protocol
would	O
be	O
spun	O
off	O
into	O
its	O
own	O
company	O
,	O
Dapper	O
Labs	O
,	O
and	O
raised	O
$12	O
million	O
from	O
several	O
top	O
venture	O
capital	O
firms	O
and	O
angel	O
investors	O
.	O
</s>
<s>
On	O
May	O
12	O
,	O
2018	O
,	O
a	O
CryptoKitty	B-Protocol
was	O
sold	O
for	O
$	O
140,000	O
.	O
</s>
<s>
In	O
May	O
2018	O
,	O
CryptoKitties	B-Protocol
launched	O
their	O
first	O
celebrity-branded	O
CryptoKitty	B-Protocol
with	O
Stephen	O
Curry	O
,	O
an	O
American	O
professional	O
basketball	O
player	O
.	O
</s>
<s>
As	O
part	O
of	O
the	O
partnership	O
,	O
Curry	O
was	O
given	O
three	O
CryptoKitties	B-Protocol
with	O
special	O
imagery	O
,	O
the	O
first	O
of	O
which	O
he	O
put	O
up	O
for	O
auction	O
.	O
</s>
<s>
In	O
October	O
2018	O
,	O
CryptoKitties	B-Protocol
reached	O
the	O
milestone	O
of	O
1	O
million	O
cats	O
being	O
bred	O
with	O
a	O
volume	O
of	O
3.2	O
million	O
transactions	O
on	O
its	O
smart	B-Application
contracts	I-Application
.	O
</s>
<s>
In	O
November	O
2018	O
,	O
Dapper	O
Labs	O
,	O
which	O
was	O
spun	O
out	O
of	O
Axiom	O
Zen	O
as	O
the	O
developer	O
of	O
CryptoKitties	B-Protocol
,	O
raised	O
an	O
additional	O
$15	O
million	O
in	O
a	O
venture	O
round	O
led	O
by	O
Venrock	O
.	O
</s>
<s>
In	O
2018	O
,	O
CryptoKitties	B-Protocol
was	O
used	O
by	O
the	O
German	O
museum	O
ZKM	O
Center	O
for	O
Art	O
and	O
Media	O
Karlsruhe	O
to	O
showcase	O
blockchain	O
technology	O
.	O
</s>
<s>
A	O
CryptoKitty	B-Protocol
's	O
ownership	O
is	O
tracked	O
via	O
a	O
smart	B-Application
contract	I-Application
on	O
the	O
Ethereum	B-Application
blockchain	O
.	O
</s>
<s>
Each	O
CryptoKitty	B-Protocol
is	O
represented	O
as	O
a	O
non-fungible	O
token	O
using	O
the	O
ERC-721	O
token	O
standard	O
on	O
Ethereum	B-Application
.	O
</s>
<s>
Generation	O
0	O
CryptoKitties	B-Protocol
were	O
sold	O
to	O
players	O
in	O
an	O
auction	O
at	O
the	O
rate	O
of	O
one	O
every	O
15	O
minutes	O
(	O
672	O
per	O
week	O
)	O
for	O
one	O
year	O
.	O
</s>
<s>
New	O
CryptoKitties	B-Protocol
are	O
created	O
by	O
breeding	O
existing	O
CryptoKitties	B-Protocol
.	O
</s>
<s>
Each	O
cat	O
has	O
a	O
distinct	O
visual	O
appearance	O
(	O
"	O
phenotype	O
"	O
)	O
determined	O
by	O
its	O
immutable	O
genes	O
(	O
"	O
genotype	O
"	O
)	O
stored	O
in	O
the	O
smart	B-Application
contract	I-Application
.	O
</s>
<s>
Until	O
November	O
2018	O
,	O
Axiom	O
Zen	O
intended	O
to	O
continually	O
release	O
a	O
new	O
CryptoKitty	B-Protocol
every	O
15	O
minutes	O
,	O
with	O
the	O
rest	O
of	O
supply	O
determined	O
by	O
breeding	O
of	O
CryptoKitties	B-Protocol
.	O
</s>
<s>
CryptoKitty	B-Protocol
owners	O
may	O
put	O
them	O
up	O
for	O
sale	O
via	O
an	O
auction	O
for	O
a	O
price	O
set	O
in	O
Ether	B-Application
(	O
ETH	O
)	O
.	O
</s>
<s>
They	O
could	O
also	O
put	O
them	O
up	O
for	O
sire	O
,	O
where	O
another	O
player	O
can	O
pay	O
to	O
breed	O
with	O
a	O
specific	O
CryptoKitty	B-Protocol
.	O
</s>
<s>
Shortly	O
after	O
launch	O
,	O
there	O
were	O
concerns	O
that	O
CryptoKitties	B-Protocol
was	O
crowding	O
out	O
other	O
businesses	O
that	O
use	O
the	O
Ethereum	B-Application
platform	O
.	O
</s>
<s>
The	O
game	O
caused	O
an	O
increase	O
in	O
pending	O
transactions	O
on	O
Ethereum	B-Application
,	O
and	O
at	O
one	O
point	O
accounted	O
for	O
about	O
25%	O
of	O
network	O
traffic	O
on	O
Ethereum	B-Application
.	O
</s>
<s>
Ethereum	B-Application
miners	O
increased	O
the	O
gas	O
limit	O
in	O
response	O
to	O
CryptoKitties	B-Protocol
,	O
which	O
allowed	O
for	O
more	O
data	O
per	O
block	O
and	O
increasing	O
transactions	O
per	O
second	O
.	O
</s>
<s>
In	O
March	O
2021	O
CryptoKitties	B-Protocol
announced	O
plans	O
to	O
switch	O
to	O
the	O
Flow	O
blockchain	O
in	O
the	O
"	O
near	O
future	O
"	O
.	O
</s>
