from typing import Dict
from typing import Any


def colon_to_list(x: Dict[str, Any]) -> Dict[str, Any]:
    """Converts suffix integers into a list.

    Examples:
        >>> x = {"a:0": 1, "a:1": 3, "b.x:0": 10, "b.x:1": 20, "c": 100}
        >>> colon_to_list(x)
        {'a': [1, 3], 'b.x': [10, 20], 'c': 100}
    """
    update: Dict[str, Any] = {}
    for key, value in x.items():
        if ":" not in key:
            update[key] = value
            continue
        key, digit = key.split(":")
        index = int(digit)
        if index == 0:
            if key in update:
                raise KeyError(key)
            update[key] = [value]
        elif key not in update or len(update[key]) != index:
            raise KeyError(key)
        else:
            update[key].append(value)
    return update