Sorry I've missed the last couple days.  I had to take my brother to visit a college, no internet access, but I'm back for Friday, and it's a good one!  Mermail Abyssleed is a Level 7, Water attributed, Sea Serpent, with 2700 attack and 1000 defense.  This of course means two tributes, or one if you run A Legendary Ocean, although as noted, ALO isn't necessary in every Water Deck.  However, by discarding three Water Monsters to your Graveyard, you can Special Summon this card from your Hand.  Three may seem like a lot, but the Archtype works well to recycle Monsters from the Graveyard, so I don't see this as an issue.  When you do, you can target an Abyss Magic or Trap card in your Graveyard and add that target to your Hand.  There's some resource recycling I was talking about, although not in Monster form.  Also, you can tribute a face-up attack position Mermail Monster you control, to discard one card from your opponent's Hand at random.  That's another good effect, though one you can only use once per turn.  You play this Deck, you play one of this.

Ratings:

Traditional:  2.75/5 
Advanced:  3.75/5 
Art:  5/5

Today we are looking at: Mermail Abyssleed
 
"You can discard 3 other WATER monsters to the Graveyard; Special Summon this card from your hand. When you do: You can target 1 "Abyss-" Spell/Trap Card in your Graveyard; add that target to your hand. You can Tribute 1 other face-up Attack Position "Mermail" monster; send 1 random card from your opponent's hand to the Graveyard. You can only use this effect of "Mermail Abyssleed" once per turn."
 
I love mermails! Since release I have been testing through the different versions, and am going to be running vortex mermails this regionals. Mermails are one of those amazing types that is not only overpowered, but also fun to play. (Unlike an otk deck, etc. )
 
Looking back to the card we have a powerhouse. You are probably not going to special summon him with his own effect, Lind or sphere do that better, and you wouldn't normally have a target sphere/scorn/squal in the grave anyway. But it is nice to have the option to use those in fire situations.
 
Now his on field effect is a personal favorite. With a mermail deck it's kind of silly how easily you can swarm the field, so the cost doesn't matter all that much, but the effect can completely cripple an opposing strategy when used at the right moment. Force a discard, get the effect of the discarded monster (providing timing allows full effect), AND load the grave for squal or an elemental lord discard? Amazing.
 
While they may not normally use this card over yonder in the ocg meta, in the us it is a powerhouse that atleast deserves consideration. And, being level 7 he can make a big eye to steal something and then be fodder for deck devastation virus.
 
I could say more, but I would just go on indefinitely, because he is just that good. 
 
Advanced: 5/5 (In mermails of course) 
Traditional: 3/5 (He is surprisingly playable here)