Blackmail is obviously pretty strong--they have three cards in their hand, you get to (often before they get a turn) look at these cards, and remove one
Playtest cards are a fantastic alternative for use in casual games and at community-organized, non-DCI-sanctioned events
Thanks to this, its no wonder that Ragavan is so expensive Right
For 4 mana, you get the effect of Entomb and 2 copies of Natures Spiral allowing you to set up for some pretty powerful plays
Elemental Summoning is impressive enough to be fearsome in the wrong hands, but in this state -with ink and water still twisting together its big jelly fangs are still cute
That last one is a particularly odd choice given its only shown up on a single card after its initial introduction in 2008's Shadowmoor block, but Heggen says it was explicitly used as a visual joke here: the symbol looks like the quarter-circle joystick motion required to do Ryus Hadoken ability in the video games