The Can't-See-'Ems are recurring characters in The Backyardigans.
The Can't-See-'Ems are insects so small that they cannot be seen clearly, unless they are grouped together. The bugs are only repelled by Bug-Away Spray and can be scattered by strong winds. Yucky Man is able to summon these insects and has used them in an attempt to stop superheroes from saving the world.
The Can't-See-'Ems appear to be small white specks in "The Heart of the Jungle". They are a dark green color in "Race to the Tower of Power" and navy blue in "The Swamp Creature". They each have two wings that buzz rapidly.