Grenade

Grenades are the weakest type of explosives and only damage mobs and players (not tiles) when thrown. They can be bought from a demolitionist for 75 copper each or found (rarely) in chests. Once hardmode is activated they can be found in pots (replacing shurikens).

A thrown grenade will bounce slightly and roll until it either hits a valid target or 3 seconds have elapsed, after which it will explode.

Like all explosives, Grenades still damage players while PvP is off, dealing 60 base damage.

Grenades are handy against large numbers of enemies. A strategy to adapt during Blood Moons is to block off the doors and wait for the Zombies to accumulate. Once dawn has arrived and they are about to retreat, toss a grenade into them. This will reap a considerable amount of money with little effort.

Grenades can also be effective against the Devourer and the Eater of Worlds.

Because grenades automatically explode when they hit an enemy, using grenades as short-ranged weapons is risky as they can easily cause self-inflicted damage.

Using grenades against a Caster AI enemy is especially inadvisable. The grenade can easily explode upon hitting one of the enemy's projectiles, often much closer to the player than anticipated.

Trivia

 * Using grenades with frost armor's set bonus causes frostburn grenades, which do much more damage than the grenade's average, and in some cases, more than double.
 * Grenades are extremely useful early-game, dealing massive damage for such an easy weapon to acquire.