Rat Colony gets +1/+0 for each other Rat you control.
A deck can have any number of cards named Rat Colony.
 
Rarity:C
#:101
Card Type:Creature — Rat
P / T:2 / 1
Flavor:Wreckage from the Phyrexian Invasion provided the rats with a seemingly unlimited number of breeding grounds.
Casting Cost:
1B
Artist:Suzanne Helmigh
TCGplayer Tip:Inspired by Relentless Rats from Fifth Dawn, Rat Colony encourages you to play as many copies as you can get your hands on, since they only get better in multiples. It works great as filler in any Rat tribal deck.