Murgkphla, Legacy's Keeper

Frog creatures you control have offspring {x}, where
X is 10 minus the number of cards in your hand.
(You may pay an additional {x} as you cast this
spell. If you do, when this creature enters, create a
1/1 token copy of it.)

If the ''legend rule'' would apply to a creature you control, put a +1/+1 counter on that creature and ignore the legend rule for as long as Murgkphla, Legacy's Keeper is on the battlefield.