Sludge Monster [Innistrad: Double Feature] League Tokens 2013 and it has "{2}{U}{U}: Return

and it has "{2}{U}{U}: Return this creature to its owner's hand at the beginning of the next end step

Set: Secret Lair Drop Series Type: Legendary Enchantment Creature — Horror Rarity: Mythic Cost: {4}{B}{B}{B} Arvinox

if you haven't added mana with this ability this turn

plastic and resin models and miniatures

Sludge Monster [Innistrad: Double Feature] League Tokens 2013 and it has "{2}{U}{U}: ReturnSet: Innistrad: Double Feature Type: Creature Horror Rarity: Rare Cost: {3}{U}{U} Whenever Sludge Monster enters the battlefield or attacks, put a slime counter on up to one other target creature. Non Horror creatures with slime counters on them lose all abilities and have base power and toughness 2 2. Tracking it isn't the hard part.