This is one of our garden plants, a chiltepin pepper plant to be exact (which is delicious and hot but another post altogether).  The three brown things on the leaf are “aphid mummies”.  These aphids were once green, alive and walking around.  That is until they were killed by a parasitic wasp in the insect family Braconidae.  The pregnant female wasp injects her eggs directly into the living aphids with her hypodermic needle-like ovipositor (literally “egg placer”).  Take a look at this picture by Alex Wild of a wasp jabbing her ovipositor into an aphid to inject her egg.  After the egg is laid and the wasp develops (feeding on the living fluids and tissues inside the aphid), it chews its way out and flies away.  Take a look at this picture from the University of Wisconsin.  The aphid mummy at the top of the leaf has a circular exit hole from where the wasp chewed its way out to fly away.