The elegant solution was to have Master of Waves create 1/0 creature tokens, then have the Master of Waves give them +1/+1
Megamorph takes away a bit of your choice in the matter, as it encourages you to play creatures face-down so you can get the counter (but many Morph creatures had abilities from being turned face up, so its not radically different)
This plays into the nature of the story of the drop, trying to take down a 'big bad.' The cards featured in the drop are all fantastic, and even the lowest-value card, Lightning Bolt, is a staple in every format it's legal in
Is it because theyre super special, vanishingly rare, almost legendary in their scarcity
Toxrill slowly weakens your opponents creatures until they die
It was infamously printed with the text "...then Floral Spuzzem may choose to destroy a target artifact ...", so it sounds like your creature should be choosing whether or not to destroy the artifact and not you (the controller of the creature)