Instant, XG (1) Play Choking Vines only during the declare blockers step. X target attacking creatures become blocked. Choking Vines deals 1 damage to each of those creatures. (This spell works on unblockable creatures.)1
Illus. Ted Naifeh
Remember that a creature with Trample which is blocked but has no actual creatures blocking it to which it can assign damage, deals its damage to the defending player. This makes this spell not very effective against Trample creatures. [D'Angelo 1997/06/12] See Rule 502.9.
Will make any creatures it targets become blocked, even if the creature had blocking restrictions on it. For example, you can make an Islandwalk creature become blocked even if the defending player has Islands. This is because evasion abilities only prevent creatures from being assigned to block them. [D'Angelo 1997/06/20]
This spell can only target attacking creatures which means it is usually played after attackers are declared and either before or after blockers are declared. [D'Angelo 1999/07/10]
You can declare zero targets, with X=0. [Duelist Magazine #19, Page 34]
Weatherlight
(Common)