add up the total ATK of all other face-up Attack Position monsters you currently control, then during the Battle Phase of this turn only, the monster gains that much ATK, but cannot inflict Battle Damage to your opponent, also other face-up Attack Position monsters cannot attack
Nissa, Steward of Elements I am taking a bit of punt with this one as yet she remains rather untested
Other high-priced serialized cards from the set have sold similarly small amounts on TCGPlayer, and its very possible these will start dropping in value as sales dry up
C Common Skull Conductor X DARK Level 4 [ ZombieEffect ] ATK 2000 DEF 0 If this card is face-up on the field at the end of the Battle Phase: Destroy this face-up card
combo route, use your remaining 4 level 4 monsters to XS into 2 different sets of rank 4 Xyz monsters, which provide disruption to your end board