Velguarder

Velguarder (ベルガーダー) is Sigma's pet dog/wolf. X will face him before facing Sigma himself in Mega Man X. Velguarder's weakness is Shotgun Ice (provided that the Hadouken wasn't acquired earlier). In Mega Man Xtreme 2, Velguarder is the first boss of the final stages.

Velguarder has also a short appearance in the opening scene of Mega Man X5.

In Mega Man X: Command Mission, a downgraded version of Velguarder makes a cameo as a mass-produced robot called Wild Dog. Wild Dogs are common enemies that appear in the Vanallia Desert.

Trivia

 * Velguarder bears a slight resemblance to Treble.