The bulette ("boo-lay"), or landshark, is a scaled reptile that resembles a mix of an armadillo and a snapping turtle that attacks prey by burrowing up from beneath them. At around 10' long, it is infamously difficult to put down or attack from range due to its natural armor, and its ability to pop up right next to weaker characters like mages makes them a menace to parties of any level. They tend to show up in areas with softer ground, such as deserts or swamps.
In Baldur's Gate: Dark Alliance, they attack you constantly in the Rotting Bog, with a much larger "Guardian" bulette as that stage's boss. They are also common encounters in the desert-set Dark Sun: Shattered Lands.