MarkB
Legend
1. What would be the general stats? I was thinking of minions, but that would obviously making them very dangerous.
Put together a minion version and a normal version, then have the minion version scattered amongst normals in a flock.
2. How much damage when they die and what area?
A close burst 1 inflicting damage similar to their basic attack should do, unless you want them to really go off like a bomb. Maybe overlay a close burst 5 that deals 1 point of damage, to set off nearby minions.
If you don't go with minions, maybe give them a property that, if another semblit explodes within 5 squares, any bloodied semblit must make a saving throw or explode in alarm.