Flying
Clockwork Avian enters with four +1/+0 counters on it.
At end of combat, if Clockwork Avian attacked or blocked this combat, remove a +1/+0 counter from it. , : Put up to X +1/+0 counters on Clockwork Avian. This ability can’t cause the total number of +1/+0 counters on Clockwork Avian to be greater than four. Activate only during your upkeep.
If the ability to add counters resolves when there are already the maximum number of counters on it, any counters over the maximum are simply not added.
04-10-2004
wotc
Can attack or block even if it has no counters.
04-10-2004
wotc
Loses a counter even if it is affected by a Fog-like effect which prevents it from dealing damage.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.
, 
: Put up to X +1/+0 counters on Clockwork Avian. This ability can’t cause the total number of +1/+0 counters on Clockwork Avian to be greater than four. Activate only during your upkeep.
