A rooster who is no longer the only tailfeather-plumed dude in the barnyard who enjoys "ultimate privileges" with "the ladies".
I unexpectedly acquired several dozen additional hens from a neighbor who was thinning his own flock, and so I had to add a couple roosters to "keep up with demand"... my original daybreak-crower was none too pleased to be cluckolded like that.
When multiple people enter an establishment to make only a single transaction, unnecessarily complicating a simple job by sheer weight of numbers.
Five students holding a table by ordering a single beer; that's a clustomer.
I'll call you back, a clustomer just walked in. I'll need a drink after this.