It's a green Mutant with base power and toughness 3/3
This IS an equipment, and RW cares about that, so it probably gets played more often than it would in most formats Lots of sets lately seem to have an Artifact that is a removal spell, and it is nice that you can play them in any deck, but they tend to be pretty inefficient, and thats kind of the case here
Murktide Regent is just a big dumb flying creature, but its really good at being big, dumb, and flying
Slither Blade Its little and low impact, yes, but Slither Blade is also unblockable and its a rogue
Not legal in sanctioned tournament play
The Fire Crystal makes your red spells cheaper, which helps you to double-spell and keep turns explosive, and it also lets your creatures attack the moment they hit the board, so you stay on the front foot