you can use this for HEAVY melee stacks
just use 1 MELEE unit (with decent Hp)
and move it fast to the enemy ranks
cast last hero on it
(depending on how many turns it has left) it wouldn't die
since the thing is mostly on 3
when u move PRESS WAIT first and let enemy attack to make sure you gain the most benefit from your last hero spell
depending on your intelligence this could last longer IIRC
which is very nice
u can steamroll darion with this tactic since they are suckers for closest unit to attack
but beware of ranged stacks