Artifact Creature - Beast 0/4, 6 (6) Clockwork Beast comes into play with seven +1/+0 counters on it. At end of combat, if Clockwork Beast attacked or blocked this turn, remove a +1/+0 counter from it. {X}, {T}: Put up to X +1/+0 counters on Clockwork Beast. This ability can't cause the total number of +1/+0 counters on Clockwork Beast to be greater than seven. Play this ability only during your upkeep.1
Illus. Carl Critchlow
Can attack or block even if it has no counters. [Aahz 1995/05/15]
Loses a counter even if it is affected by Fog or a Fog-like effect which prevents it from dealing damage. [WotC Rules Team 1995/04/26]
If the effect to add counters is used when there are already 7 counters on it or when the number of counters to be added would cause it to exceed 7 counters, any counters over 7 are simply not added. [D'Angelo 1997/02/09]