Tiny eggs:

Get to Level 4-3 (Piranha Grove.) Get swallowed by 
the Piranha Pest (the flying plant) and use the 
lifts to jump up to the Egg Block once you're small.
Hit the Egg Block and the eggs will pop out, only 
they will be tiny! Plus, when you grow back again, 
you can get these tiny eggs to throw! Of course, 
they pack the same pop as regular eggs, they're 
just small.