You technically can put multiple regeneration effects on a permanent at once, but the multiple effects serve no real purpose and will all go away the next time the permanent would be destroyed that turn
Batterskull can even return itself to its owner's hand to dodge removal effects or make another Germ, and this card appears in a variety of decks
---------------------------- When melded, it becomes the following: Legendary Creature Beast Avatar Vigilance, menace, trample, reach, haste When Ragnarok dies, destroy target permanent and return target nonlegendary permanent card from your graveyard to the battlefield
Zealot does not have hexproof, but the higher toughness makes it hard for Red removal to kill it
Some players also use it in frog decks for flavor reasons, even though Sab-Sunen doesnt have the frog creature type