C/5 wickstretcher (unstabilized) in that rule:

`x = 18, y = 401, rule = B2-an3-cery4city5kqry6-ck7c8/S`

7bo2bo$2bo2bobo2bobo2bo$6bob2obo$o2b2o8b2o2bo$bo5b4o5bo$b3o3bo2bo3b3o$

4bo3b2o3bo$2bo3bo4bo3bo$4bo3b2o3bo$7bo2bo$4bo8bo2$3b3o6b3o2$b7o2b7o2$

2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b

3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o

2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b

5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o

2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$

2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b

3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o

2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b

5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o

2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$

2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b

3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o

2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b

5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o

2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$

2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b

3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o

2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b

5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o

2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$

2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b

3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o

2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b

5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o

2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$

2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o2$2b5o4b5o2$3b

3o6b3o2$b7o2b7o2$2b5o4b5o2$3b3o6b3o2$b7o2b7o!

EDIT, and an actual C/5:

`x = 20, y = 64, rule = B2-an3-cery4city5kqry6-ck7c8/S`

8bo2bo$3bo2bobo2bobo2bo$7bob2obo$bo2b2o8b2o2bo$2bo5b4o5bo$2b3o3bo2bo3b

3o$5bo3b2o3bo$3bo3bo4bo3bo$5bo3b2o3bo$8bo2bo$5bo8bo2$4b3o6b3o2$2o2b4o

4b4o2b2o$3bobobo4bobobo$2bo14bo$8bo2bo$4bo3bo2bo3bo$5bo8bo$3b3obo4bob

3o2$3b2o2bo4bo2b2o$6bo6bo$5bo2b4o2bo$8bo2bo$9b2o$2b5ob4ob5o2$9b2o$2bo

14bo$7b6o$b5o8b5o$9b2o$3o14b3o$4bo10bo$2b2obo8bob2o$5bobob2obobo2$8bo

2bo$2b3o4b2o4b3o$8bo2bo$5bo8bo2$3b3o8b3o$2bo14bo$2bob3o6b3obo$6bobo2bo

bo$3b2o3bo2bo3b2o$6bo6bo$9b2o$6bo6bo2$4bo4b2o4bo$3b2o4b2o4b2o$3bo2b3o

2b3o2bo$3bo2bo2b2o2bo2bo$6b2o4b2o$3bob2o2b2o2b2obo$3b2o2b2o2b2o2b2o$7b

o4bo$4b2o8b2o$7bo4bo$5bo8bo!

EDIT 2, a C/6:

`x = 11, y = 24, rule = B2-an3-cery4city5kqry6-ck7c8/S`

5bo$5bo$2bob3obo$bo3bo3bo$3o2bo2b3o$o4bo4bo$2bo5bo2$3bo3bo$5bo2$4bobo$

4bobo2$4bobo$2bo5bo$2b2o3b2o$o9bo$3b2ob2o$3bobobo$3bobobo$5bo$5bo$5bo!

EDIT 3, a C/7:

`x = 12, y = 12, rule = B2-an3-cery4city5kqry6-ck7c8/S`

o10bo$o10bo$o10bo$2bo6bo$ob3o2b3obo$bobo4bobo3$5b2o$o2b6o2bo2$3ob4ob3o

!