The higher the star rating, the stronger the Monster is and the more conditions that must be met to summon it, like sacrificing another Monster, or special-summoning it with a Spell card
Additionally is missing the external black line
it evolves when you play a bigger creature, which lets it tap for more mana, allowing you to play a bigger creature to trigger evolve again, so you can tap it for even more mana, and so on
If you have high end cards that you want to provide extra protections for, you may place the card between two sleeves
ST Starfoil C Common Gagagabolt X SPELL If you control a "Gagaga" monster: Target 1 card on the field
Drawn by the incredibly talent Taiga Kayama, the artist also behind the adorable Vanilish Illustration Rare from Paradox Rift, this Clive card feels like something ripped straight from Animal Crossing