Serum Tank

At the beginning of each upkeep, each player exiles the top card of their library. The player who exiled the card with the greatest mana value takes an extra turn after this one. If two or more players' cards are tied for greatest, the tied players repeat this process until the tie is broken.

1G, T: Counter target activated ability from an artifact source. (Mana abilities can't be targeted.)

T: Add R.

Whenever a player casts a creature spell, that player adds G.

1R: This creature gets +2/+0 until end of turn.

Whenever you cast an artifact spell, draw a card.

Equipped creature gets +2/+0. Equip 1

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle. When this creature dies, you may draw a card.