Knobby White Spider

{bold}Vigilance{/bold} Knobby White Spider’s power is equal to 1 plus the number of incubation counters on it. Whenever this creature deals combat damage to an opponent, put that many incubation counters on it. Whenever damage is dealt to you, clear all incubation counters on this creature: Create a green 1/2 spider token for each counter removed this way. Whenever this creature has twenty or more incubation counters, transform it.