Rarity Leader Card x 1, Super Rare x 2, Rare x 3, Common x 8, Uncommon x 1
If another monster is Special Summoned to a zone a Link Monster points to, while this card is in the Extra Monster Zone: Apply 1 of these effects (but you cannot apply that same effect of "Topologic Blaster Dragon" again this turn)
Rotting Regisaur Pre-2010 or so, Rotting Regisaur would have had a more restrictive drawback--I'm thinking specifically a Masticore-style "at the beginning of your upkeep, discard a card or sacrifice Rotting Regisaur." Instead, M19 gave us a more modern design, which doesn't require a discard if you're hellbent and prevents the miserable feeling of top-decking a Masticore when you're desperate for a creature and out of cards in hand
Not only can you play it for two mana and get in some early extra damage, but you can also play it for four mana and start protecting your team from disaster
And let me tell you, the latter happens more than the former
Determine the amount of energy you need