In Intelligent Design, these mass extinctions are referred to as God's "DO OVERS"
What's fascinating about the Cretaceous mass extinction was that had that 6-mile rock hit anywhere else on the surface of the earth, there would be no mass extinction resulting. The fall targeted a huge limestone bed, the burning of which caused the nuclear winter/mass extinction that resulted. There are only two such limestone beds of similar size on earth: Yucatan, and Dover. Talk about a bullseye! (or maybe a T-rex eye, as the bull hadn't evolved yet.)
Appropos of nothing, do you know the derivation of the name "Yucatan"? It seems the Spaniards landed there in 1520, and said (in Spanish): "What is this place called?" To which the local inhabitants naturally responded: "Yectetan!" Which is the local language for "I don't understand you!" (The kangaroo got its English name by a similar process.)
Sorta like putting the beakers in an autoclave!!!