The Sticky Barb.
For those unfamiliar with it, it's a held item introduced Gen 4 that damages the holder each turn (1/8 of Max.HP to be precise).
If the holder is hit by a physical attack, it may latch on to the attacker, damaging them each turn. However, if the attacker is already holding an item, the Sticky Barb can't move.
Here are some pros and cons I can think of from the top of my head:
Pros:
+ Encourages new strategies in competitive battling
+ Improves the economy with yet another item to trade/sell
+ Can be used to counter Physical sweepers
+ Can be used to counter Trick/Thief/Cover users
+ Could be added as a Held item for Cacnea (once Hoenn is implemented)
Cons:
- May cause chaos if two physical attackers are attacking each other (i.e. the barb would keep moving around)
- Could be problematic if all Pokémon on the opposing team already have held items
Any thoughts on this? If I missed anything obvious, slap me comment below.