Arachnid Infestation

When Arachnid Infestation enters the battlefield,
put a Web counter on X target permanents
you don't control.
Whenever an opponent attacks with, blocks with,
or activates an ability of a permanent with a Web
counter on it, create a 1/2 green Spiderling
creature token with Reach.
Careful through these woods, don't disturb the nests!