In Mega Man 5 you get these M-Tanks which are very helpful. Just like the E-Tank, they restore all of your life energy, but unlike the old-fashioned E-Tanks, they restore all of your weapon energy as well.

But, what would happen if you already had full everything when you used your M-Tank, hm?

Well, you would hear the sound like you collected a 1UP, and all non-boss enemies on the screen would turn into 1UPs!

Which is very handy for stocking up on lives before taking on a particularly tough challenge.