Reanimate, Life/Death, and good old fashioned attacks from your opponents can put a strain on your life total, so having an option for mitigation can get you through some tough spots
Chainers Edict, Consuming Vapors, Custodi Lich, Dead Drop, Devour Flesh, Diabolic Edict, Gatekeeper of Malakir, Geths Verdict, and others are among just a few of the spells that can cause an opponent to sacrifice a pro-black critter
Rattata can be obtained from Shining Revelry pack in the Shining Revelry set
Due to its low mana cost, Esper Sentinel is generally more effective in constructed formats but still packs a punch when played early
Free's views on the topic seem to look at intent and degree when defining a scalper
On a fake card : Holography is often too shiny or printed on the surface It can cover the entire card inconsistently