Peel the bananas and trim a small slice off the bottom of each so they stand flat. Insert one popsicle stick into the cut end of each banana, pushing it about halfway up.
In a bowl, stir the Greek yogurt and vanilla extract together until smooth. Hold each banana by the stick and dip it fully into the yogurt mixture, letting excess drip off.
Place the coated bananas on a parchment-lined tray. Press two mini chocolate chips into the upper half of each banana for eyes. Add one more chip lower down to form a mouth if desired.
Transfer the tray to the freezer and leave the pops until the yogurt coating feels firm, about three hours. Remove and serve straight from the freezer.