When a creature with mentor attacks, you put a +1/+1 counter on an attacking creature with lesser power
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 Gibbering Fiend: The card types in Magic are artifact, battle, creature, enchantment, instant, kindred, land, planeswalker, and sorcery
It's another Avatar card, so still fairly new, but I'd expect this to show up a lot in 2026 and beyond, especially if it flops in Constructed and the price ever settles down
The player whose turn it is discards down to their maximum hand size
With one of the best anime alt-arts seen so far in MTG, this card is likely to remain in Ravnica Remastereds top spot for some time yet