The ornamental design for a octopoolcue, as shown and described.
FIG. 1 is an elevation view of a octo pool cue showing my new design, The broken line showing of the front section of the pool cue shown in broken lines is for illustrative purposes only and forms no part of the claimed design;
FIG. 2 is an enlarged elevation view thereof, the undisclosed left, right and bottom sides being identical;