[15] Key mechanics: Devour, haste, graveyard shenanigans, and anything midrange
Another thing that hurts the cards playability in cube is the reasonably large number of cards you don't really want to play with it such as countermagic, combat tricks and other time critical or narrow cards
You can always target your own Army token if your opponent has protection from their One Ring, and since the ability is simultaneous your token wont die during this process (provided there is no damage already on it)
White decks not in red get an Inventory Management effect in Battlefield Improvisation
Cards like Gray Merchant of Asphodel or lifegain strategies make paying 5-8 life trivial compared to the board control achieved
Whether you like SpongeBob now being a part of MTG or not, the cartoon character's Secret Lair was seemingly as popular as most of the other crossovers to have come before it