He is chasing squirrels now, following an afternoon spent raging at his own shadow.

An afternoon spent zigging and zagging, turning left and dodging right.
Barking at figments and filtered light. Showing his teeth to an illusion, hair bristled, growl caught in the back of his throat.

Not realizing he was being played; looking down instead of up.

Only when the light shifted, did he realize the squirrels, hoarding their bounty, safe above the fray, were laughing at his expense while he waged war with himself.