Vraska's ultimate gets an opponent to nine poison counters, and a single attack or proliferate will finish things off from there
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
Free's views on the topic seem to look at intent and degree when defining a scalper
Rattata can be obtained from Shining Revelry pack in the Shining Revelry set
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
There's a big difference between deck-building intent and what happens in the game