The taco is a food item, which heals four whole hunger points.
W=wheat V=vines P=cooked pork chop N=nothing
The taco drops from yellow bloons, skeletons and zombies. It also is an uncommon (not rare) find in dungeon, village, and stronghold chests. Butchers and farmer villagers can also trade these to you (Costs: Butcher=2-5 Farmer=4-6).