One of 30 uniquely numbered Pikachu cards is guaranteed in every pack, each drawn by a different artist
The most valuable Gengar cards typically include 1st Edition holographic cards from early sets, Gold Star variants, Alt Art cards from modern sets, and promotional cards with limited distribution
Its relatively expensive at 5 mana, but in Commander and Cube (where this sees play), its a powerful effect
The backside is a sorcery that has a whole plethora of effects including card draw, removal, some +1/+1 counters, and even copying a permanent you control
To move a counter from one permanent to another, the counter is removed from the first permanent and put on the second