If you play something like Elves, Goblins, Humans, or Merfolk, you can fill your deck with 30 creatures of the right type and never worry about your mana curve because these creatures exist at all reasonable points in the curve, but if you ever play 30 Giants in a deck, then the average converted mana cost will be five and you will lose most games without ever casting a spell
Its a tried-and-true strategyturning chip damage into a flood of cards
When you do, put a +1/+1 counter on each creature you control
PSA 10 price: higher in graded and special versions
Activating that rat-doubling ability requires a sacrifice, unlike Krenko, which works well for a mono-black death strategy and pairs nicely with the rats that are good sac fodder or sac and death payoffs
Due to not wanting to attack with 5/5 Gideon if you are behind on the board, you tend to just churn out 2/2s and as such you never work up a buffer of loyalty