I played four copies over eight rounds of Modern last weekend and there were very few moments when it functioned differently from it would have read Counter target spell or destroy target creature. Im not arguing that its exactly that, or that it doesnt require any work, but a card that literally did that would be so far above the rate were used to seeing for interaction that if Drown in the Loch doesnt do what you want 10% of the time, its still among the best two-mana interactive spells in Modern, which is precisely how I rate it
Flying At the beginning of your upkeep, put the top card of your library into your graveyard
Cache Grab fits into the food synergies that squirrels in Bloomburrow are doing most of the time
A staple of removal
It can amount to the accelerated life loss from a Phyrexian Arena, but it doesn't need to reach max speed so if you're stuck in second gear, you still double up on the staple black enchantment and good card draw
Only creatures you control at the time Song of Totentanz resolves, including the Rat tokens it creates, will gain haste