Simple Example Image Facing Mouse

import pygame

TRANSPARENT = 0, 0, 0, 0

# Image Orientation Matter. Right Side Is Top
def create_triangle(size, color):
    rect = pygame.Rect((0, 0), size)
    surface = pygame.Surface(size, pygame.SRCALPHA)
    surface.fill(TRANSPARENT)
    points = rect.midright, rect.bottomleft, rect.topleft
    pygame.draw.polygon(surface, color, points)
    return surface

def rotate_image(sprite, target):
    vector = pygame.Vector2(target) - sprite.rect.center
    # Second Value Is The Angle
    angle = vector.as_polar()[1]
    # Always Rotate From Original Image. Rotate With Negative Angle Because Topleft Is (0, 0)
    sprite.image = pygame.transform.rotate(sprite.original_image, -angle)
    sprite.rect = sprite.image.get_rect(center=sprite.rect.center)

def main(caption, width, height, flags=0, fps=60):
    # Simple Pygame Setup
    pygame.display.set_caption(caption)
    surface = pygame.display.set_mode((width, height), flags)
    rect = surface.get_rect()
    clock = pygame.time.Clock()
    running = True
    delta = 0
    fps = fps

    # Variables
    background_color = 'black'
    triangle = pygame.sprite.Sprite()
    triangle.image = create_triangle((50, 50), 'dodgerblue')
    triangle.rect = triangle.image.get_rect(center=rect.center)
    triangle.original_image = triangle.image

    # Main Loop
    while running:
        for event in pygame.event.get():
            if event.type == pygame.MOUSEMOTION:
                rotate_image(triangle, event.pos)
            elif event.type == pygame.QUIT:
                running = False

        # Logic

        # Draw
        surface.fill(background_color)
        surface.blit(triangle.image, triangle.rect)

        # Render Buffer To Screen
        pygame.display.flip()
        # Idle And Get Delta Time
        delta = clock.tick(fps)

pygame.init()
main('Facing Towards Mouse', 800, 600)
pygame.quit()