The Earth Crystal There are a lot of +1/+1 counters matter decks out there, and almost every single one will want The Earth Crystal
Creatures with activated coin flip abilities are even better because you get to choose if you even want to take the risk
You may play lands and cast spells from among cards exiled this way without paying their mana costs
The synergy with Mox Diamond and Scroll Rack was what really pushed the card over the edge, however
Aboshan dies easily for a six mana creature - that three toughness is below the threshold for red commons in the draft (Fiery Temper, Firebolt with flashback, Flame Burst with another Burst or Pardic Firecat in the yard, Acceptable Losses, Swirling Sandstorm, Kamahl's Sledge, Sonic Seizure, and Ember Shot will kill it), making it a little too fragile to survive in most instances
This card also comes in Legendary rarity, which is hitting highs of $40 during pre-market sales