At the beginning of combat on your turn, another target creature you control gains Haste and gets +X/+X until end of turn, where X is that creatures power
Some of our creatures can end up lethally large
That said, its popularity and place on this list are more than earned, as it remains an efficient foundation to build a Reanimator strategy upon
Then, if its a Land card, you can put it into play tapped, and if its not, you get to draw it
Playing Xorn on curve is a mistake unless you are creating treasure tokens by attacking with a creature like Hoard Robber, or are casting an Instant that turn which produces a Treasure token
But first, a quick disclaimer: Risk of Investing in MTG While I have made money as both a collector and investor in MTG products, my perspective is only one among many, formulated by my past experiences