The Crab first got the milling ability based on the logic I explained above in Drowner Initiate
White and Red has almost nothing
Hardened Scales and Inspiring Call are fine, but Branching Evolution is just an overcosted Scales in this deck because we're never adding more than one +1/+1 counter at a time
Tyranid Invasion is great early (since you usually have three opponents), Tyranid Prime is absolutely bonkers, one of the best cards in the deck, and Tyrant Guard is pretty good, offering protection to your board
Rikku, Resourceful Guardian allows you to force a creature through your opponents' blockers, as well as steal counters, and Lulu, Stern Guardian protects you by putting stun counters on your opponents creatures, as well as proliferating to keep them around
Okay so this Plasma Caster might be true RNG outside a coin flip deck (a deck where itll be awesome), but I think you can generate some virtual card advantage by playing this thing anyways