Musharna (NXD #59) has a very similar ability to Slurpuff (PHF #69), with the drawback of not being available on current standard format. On the other hand, it has two basic advantages over Puff:
1. It can naturally be paired with Munna (BCR #68), that has the ability Long Distance Hypnosis, and can be used to stall attacks from your opponents while you wait for a Musharna -- very important on a Seismitoad mirror-match. (of course you risk your Seismitoad being put to sleep instead, but there is a number of things you can do to avoid having any conditions on your active mon, from Keldeo (BCR #49) to Virizion (PLB #9), and also Sparking Robe (FUF #99)).
2. Although Puff allows you to draw an extra card sometimes, the number of times you effectively do this is very limited (2 or 3 times per game, maybe?). On the other hand, Musharna allows you to draw the same number of cards while on your bench as Puffs, but the last Musharna you use allows you to choose between the two top cards on your deck EVERY TURN that this card is in play and it's ability is not blocked, which can give you some advantage.
Besides that, Musharna is allowed on a format that also have Level Balls (NXD #89) and Heavy Balls (NXD #88), which allows you to look your deck for Munna's, and Musharna's or Seismitoad's without having to discard cards from your hand =)
I hope this helps =)
PS: Also, Musharna is a stage 1 Psychic type, which means the only way to block it's ability is via Garbodor (LTR #68), and attaching a tool to it while you're quaking punching with Seismitoad is kind of difficult for you opponent (things like Wobbuffet [PHF #36] can block puffs, and make your game a lot slower).
