Guardians of Koilos

When this creature enters, return a nonland permanent you control to its owner's hand.

At the beginning of your upkeep, if you control seven or more permanents, return this creature to its owner's hand.

Flying

This creature enters with six +1/+1 counters on it.

, Remove a +1/+1 counter from this creature: Put a flying counter on another target creature.

, Remove a counter from another creature you control: Put a +1/+1 counter on this creature.

When this creature enters, if you control two or more nonland, nontoken permanents with the same name as one another, create a 4/4 colorless Construct artifact creature token.

When this creature enters, for each kind of counter on target permanent, put another counter of that kind on it or remove one from it.

Prototype — 3/3

When this creature enters, return target creature an opponent controls with power less than this creature's power to its owner's hand. If that creature wasn't a token, conjure a duplicate of it into your hand. It perpetually gains "You may spend mana as though it were mana of any color to cast this spell."