When Ignit is given too much fuel for his flames he looses control.
His fire becomes too strong for him to handle and his shape becomes unstable.
When this happens he will loose all sense and his only desire is to keep fueling his now much larger form.
He will burn everything and anything he can find in order to sustain himself.
The only way to stop him is to douse his flames or to keep him away from flammable material.
However one must be careful when doing this, if his flame becomes too weak it can be fatal.