Frenzy Boar

Frenzy Boar (フレンジーボア) is a low-level monster, found in the fields beyond the Starting City, in Sword Art Online. It is a passive monster and has to be provoked first before it engages the player in combat. It is the weakest of all enemy monsters, having been compared to slime monsters of other games, and can be killed easily with one precise blow to the back of its head, its weak point. The Frenzy Boar rewards the player with 24 Exp and 30 Cor after being killed.

Appearance
Despite its low level, the Frenzy Boar appears to be a medium-sized monster with a total length of one hundred and twenty centimeters with blue fur, glowing red eyes, a flat snout and sharp tusks protruding from either side of its mouth. In contrast to its bulky size, the Frenzy Boar is capable of moving fast as it charges towards its opponents.

Aincrad Arc
When Klein first met Kirito, he begged him to show him the basics of SAO, so Kirito took him outside to the starting fields and taught him the attack basics by fighting these creatures.