Sub-grades for centering, edges, corners, and surface provide detailed insights into a cards quality
At its best you want them to draw the card you put back on top, in this way you not only deny them something in play but you also make their next draw sub optimal
So knowing this about Slugma and looking at this specific Magcargo card, I wouldn't recommend using this card in a deck
But, Elas il-kor edges out over all of these by being both in one, allowing for life gain whenever a creature enters and life loss when a creature dies
Brawl Not Legal Vintage Legal Timeless Not Legal Commander Legal Pauper Not Legal Oathbreaker Legal Penny Not Legal Toolbox Buy This Card Notes and Rules Information for Encase in Ice: If the enchanted creature stops being red or green, or if it stops being a creature, Encase in Ice will be put into its owner's graveyard