Mini Janemba
Mini Janembas are small copies of Janemba. In Hell they come as a stampede that punishes players who stay too long, and in the Janemba world boss fight the boss calls them to his side.
The stampede
Linger in Hell, below the clouds of the Otherworld (below Y 96), for 8 to 14 minutes in a row and a herd of 20 Mini Janembas comes charging at you from about 20 blocks away. The time is random, and it is rolled again each time you enter Hell and after every stampede.
As soon as one of them lands a hit, knocking you back, the whole herd scatters and vanishes in a puff of smoke. Any that are left disappear after 40 seconds.
Only survival and adventure players are targeted: being in creative or spectator mode, or leaving Hell, resets the timer, and there are no stampedes in Peaceful.
Drops
Mini Janembas drop nothing.
In the Janemba fight
During the Janemba world boss fight, Janemba calls a ring of 10 Mini Janembas when his health drops to 80%, and again at 60%. While they are alive he sits back and doesn't fight; see Janemba for the whole fight.
dragonminez:mini_janemba_stampede