Thanks for playing and glad you enjoy the game! The kudzu vines started as a “can we make this look good?” experiment before we even decided what the gameplay would be.
The vines are a Line2D with a new point added every timer tick. The width increases by number of points and a width curve creates the thinness at the leading end. Each new point starts at points[-1] and tweens to its final position, though this animation seems to get dropped a lot after switching to physics processing for vine collision with walls. The leaves have 3 stages of growth that are scaled from zero and modulated from transparent on the same timer.