Ugin's Construct

As this creature enters, choose a color.

When you control no permanents of the chosen color, sacrifice this creature.

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.

When this creature enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

: Add one mana of any color.

Trample

When this creature attacks or blocks, sacrifice it at end of combat.

When this creature enters, put a +1/+1 counter on target creature.

When this creature enters, create a tapped Powerstone token. (It's an artifact with ": Add . This mana can't be spent to cast a nonartifact spell.")