This color indicator can't be affected by text-changing effects (such as the one created by Crystal Spray), although color-changing effects can still overwrite it
On top of that, all damage is now dealt with wither, meaning it remains on creatures as -1/-1 counters instead of temporary damage that heals in the end step
In fact, summoning sickness isnt actually connected to the summoning itself but its connected to the controlling the permanent: 302.6
What makes it really shine in Elves is how the deck supports it with insane mana from cards like Gaea's Cradle or Priest of Titania and untap effects from Quirion Ranger or Wirewood Symbiote
Arabella, Abandoned Doll One red, one white legendary artifact creature Whenever Arabella, Abandoned Doll attacks, it deals X damage to each opponent and you gain X life, where X is the number of creatures you control with power 2 or less