Spell Grenades are a new type of Grenade Mod in Borderlands 2.
These were introduced in Tiny Tina's Assault on Dragon Keep DLC
The Spell Grenades is Borderlands' way of simulating spells.
Each grenade is named after a famous spell from D&D and simulate its effects.
They have zero fuse time (to simulate the casting), and slowly regenerates grenade ammo over time (to simulate spell points)