The Mega Evolution sets, featuring Mega Lucario ex and Mega Gardevoir ex, mark the trading card game's departure from its Scarlet and Violet era
Sometimes, they can be good for building your first deck, and Slugma fills the bill
This happened in Theros Beyond Death and warped the entire format around the color
But with the condition being as bad as it is, I would likely just skip the card, because its no fun to look at
The beginning of upkeep after any triggered abilities have been put on the stack is the first time a player receives priority for their turn
When you do, return target creature card with mana value X or less from your graveyard to the battlefield, where X is the amount of life you gained this turn