* Berserk Dragon's Summoning Condition: Berserk Dragon can only be Special Summoned from your hand by discarding 1 Dragon-Type monster.
* Call of the Mummy's Effect: Call of the Mummy allows you to Special Summon a Level 4 or lower monster from your Graveyard.
Berserk Dragon is Level 8, and Call of the Mummy only works for Level 4 or lower monsters. Additionally, Call of the Mummy requires a monster to be in your Graveyard, while Berserk Dragon needs to be in your hand.
Therefore, the two cards are incompatible for this specific Special Summon.