MacTusk is an aggressive mob. He's the leader of the Father and Son Walrus Hunting Party, which will respawn every 2-5 days after being killed, on a Walrus Camp. MacTusk takes two blasts from the Ice Staff to be frozen.

MacTusk uses a Blow Dart as a ranged Weapon to attack the player while trying to keep his distance. His range is very long, being able to hit the player from two screens away.The player is able to dodge his darts if timed correctly; it is advised to run serpentine/zig-zagged due to the dart's high speed.

With normal damage modifier characters, MacTusk takes 5 hits with a Spear; 4 with a Bat Bat; and 3 with a Tentacle Spike, Ham Bat, Thulecite Club, and Dark Sword to be killed.

MacTusk is usually accompanied by Wee MacTusk and 2 Blue Hounds. He is only active during daytime. He will follow the player if the player is around him. MacTusk will actively attack players if they get too close, often sending in the hounds first.

Taking out two Hounds first is priority. They're faster than the other hunting party members. It's recommended to use ranged weapons against this foe, since he will run away from the player if pursued. Using a Boomerang and some kind of armor is the easiest and the least expensive way to kill him.
If the player comes across the Walrus Camp while it is inactive, it will be prudent to set up defenses or traps, or maybe even wait there for a physical confrontation. However, waiting there could get the player overwhelmed.
If lured to a large enough pack of Pengulls, MacTusk will attack them, causing the Pengulls to retaliate and kill MacTusk (and the Hounds).
The easiest way to deal with this camp later in the game is to freeze MacTusk, then hit him, and repeat. Kill his Hounds first, as an earlier bullet point states. Wee MacTusk won't be a problem because he cannot attack on his own and will flee when the rest of the camp are dead.