Rain Slime

The Rain Slime is a Mob. Rain Slimes spawn naturally in the Spider's Den when it is raining, in the area where skeletons spawn, and at the base of the mountain. Rain Slimes give the player only, regardless of their size.

Strategy
Since slimes do not multiply upon death, players will not have to worry about that when dealing with them. Some of the larger slimes have a lot larger reach than they seem to, so if the player does not have much and can get one-shot by them, the player should probably fight them from afar with a bow. Also, because these slimes deal heavy knockback, even if the player is not killed directly from the mob, the fall damage can take out many early-game players.