For the latter timing, Werewolf can let its controlling player gain perfect knowledge of the opponents hand before banishing 1 card face-up until the end phase of the turn
Pull rate from Regular Packs: 4.50% The estimated pull rate for Crabominable (Mega Rising) from a Regular Pack is approximately 4.50%, meaning you might need to open around 23 Regular Packs to obtain it
Once again, it comes down to supply and demand
Used in decks like Legacy Lands, it can hate out any deck that relies on using creatures to get in
EarthquakeEarthquake.dec is a valid option, with instant speed versions like MagmaquakeMagmaquake and flying-inclusive options like Blasphemous ActBlasphemous Act
Once per turn, during the Main Phase, if you control no card in your Field Zone: You can activate 1 "Necrovalley" directly from your hand or GY