Board Thread:Super Smash Bros. Discussion/@comment-25581315-20141102153614/@comment-24529455-20141102182124

Do 10-Player Smash as Yoshi, and at the end you'll face off against a rather large Yoshi. Use Egg Lay on the big Yoshi and it'll grow bigger. Keep doing this and it can reach incredible size.

See Supersize Glitch for more details